Статті в журналах з теми "Β-grain"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Β-grain.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "Β-grain".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Zhang, Xue, Yi Chen, Feng Shou Zhang, Jun Ting Yang, Yun Jin Lai, Hong Chao Kou, Jin Shan Li та Lian Zhou. "Microstructural Evolution and Precipitation Mechanism of α-Phase in Ti-55531 Alloy Aged at High Temperature". Materials Science Forum 747-748 (лютий 2013): 912–18. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.912.
Анотація:
After two-stage annealing heat treatment process, the near β-Titanium alloys reveal a mixed microstructure containing lath-like α phase and finer acicular α phase in β matrix, leading to the improvement of strength-ductility balance. In this paper, the microstructural evolution and the behaviour of α precipitate during high temperature ageing process were investigated by SEM in a near β-Titanium alloy called Ti-55531.The relationship between α precipitates and the β grain orientation in high temperature was investigated by EBSD. The results show that the α-phase precipitated only at some places of the β grain boundaries at higher ageing temperature (~780 °C); the amount of grain boundary α increased with the decreased of the ageing temperature; after ageing at 720 °C for 45 min, we found that the α-phase precipitated not only at grain boundaries but also within the grains. It seems that the precipitation of grain boundary α is strongly influenced by β grain boundary energy which means that grain boundary α tends to form preferentially at high energy grain boundaries (high-angle grain boundaries); The α-phase precipitates more easily at the grain boundaries where the {110} plane of adjacent β grains have the same orientation.
2
Liu, Mingqi, and Sia Nemat-Nasser. "Microstructure of a bearing-grade silicon nitride." Journal of Materials Research 14, no. 12 (December 1999): 4621–29. http://dx.doi.org/10.1557/jmr.1999.0625.
Анотація:
The microstructure of a bearing-grade silicon nitride, prepared by pressureless sintering with Y2O3, AlN, and TiO2 additives and then hot-isostatically pressed, is examined with high-resolution transmission electron microscopy, scanning electron microscopy, and x-ray diffraction. The material consists of large acicular β–Si3N4 grains and small equiaxial α–Si3N4 grains. An amorphous phase containing the sintering aids is observed at the two-grain boundaries and at the grain pockets. No crystalline boundary phase is identified. The α-to-β and β-to-β grain boundaries appear straight and well defined. The dominant crystalline planes observed at the β-grain boundaries are (1010) and (1120). The intergranular spacing of the two-grain boundaries (α-to-β and β-to-β) is 1.0 nm when a high-contrast boundary phase is present, and it is 0.8 nm when a low-contrast boundary phase is present, confirming that the film thickness is strongly dependent on the boundary-phase composition. The α-to-α boundaries are often curved, and the thickness of the amorphous film at these boundaries varies from 0.7 to 1.1 nm. Evidence of near-intimate contact between β-grains is also observed.
3
Yan, Meng Qi, Ai Xue Sha, Wang Feng Zhang та Yu Hui Wang. "Recovery and Recrystallization Behavior of Large Sized β Phase Grains in TC18 Titanium Alloy during Annealing Process". Materials Science Forum 817 (квітень 2015): 263–67. http://dx.doi.org/10.4028/www.scientific.net/msf.817.263.
Анотація:
The manufacturing processes of TC18 titanium alloy bar takes about 10 times forging. During forging, the β phase grain experiences a series complicated process such as recovery, recrystallization and grain growth. Larger sized β phase grains can easily be formed under different conditions such as insufficient deformation or slow cooling rate during the forging process, which may affect the mechanical properties of TC18 bars. In order to find out the causes and elimination methods of large β grains, this paper used EBSD techniques to analyze the microstructure and texture of TC18 titanium bar at center layer, 1/2R layer and surface layer after the process of forging and heat treatment. Results show that a large portion of β grains experiences recovery and grain growth, while a minor portion of β grains only experiences recrystallization after α+β region heat treatment. Most β grains experience recrystallization, while for those β grains which are hard to be swallowed by recrystallized grains only experience recovery after β region heat treatment. Rather than eliminate the large sized β grains, it’s even easier for those β grains to grow up during annealing process under the condition of insufficient deformation.
4
Wang, Xiao Xiang, Wei Qi Wang, and Yong Qiang Zhang. "Effect of Heat Treatment and Thermal Exposure on Microstructure of the Alloy C+ Bars." Materials Science Forum 765 (July 2013): 506–10. http://dx.doi.org/10.4028/www.scientific.net/msf.765.506.
Анотація:
The microstructures of the Alloy C+ with three different heat treatment processes have been investigated after exposure at 550 °C for 100 hours in this study. The alloy shows typical equiaxed β grains with second phase precipitation and twin formation inside the β grains in the as-rolled condition. Solution treatment at lower temperature led to a smaller β grain size while higher temperature solution treatment produced coarse grains with increasing precipitated phases inside the β grains. Ageing treatment after solution and thermal exposure for a long period of time resulted in an increasing α phase precipitation at the grain boundaries due to their tendency for preferential nucleation of second phases. In a certain condition, continuous coarsening of the α phase is concentrated on the grain boundaries therefore violate the properties of the alloy.
5
Gerasimov, Sergey Aleksandrovich, Vadim Igorevich Polonskiy, Alena Vladimirovna Sumina, Nikolay Aleksandrovich Surin, Aleksey Gennad'yevich Lipshin, and Sanita Aldonovna Zyute. "THE INFLUENCE OF GENOTYPE AND CULTIVATION CONDITIONS OF OATS IN THE CONTENTS OF BIOLOGICALLY ACTIVE COMPONENTS IN GRAIN." chemistry of plant raw material, no. 2 (June 10, 2020): 65–71. http://dx.doi.org/10.14258/jcprm.2020025515.
Анотація:
With the aim of studying the influence of genotype and climatic conditions on the content of β-glucans, fat and protein in grain, oat samples were grown in the Krasnoyarsk territory region and the Republic of Khakassia for three years. The object was 1 naked and 2 husked samples of oats of Krasnoyarsk selection. The content of β-glucans and fat was measured on an automatic grain analyzer Infratec Analyzer 1241 using 50 ml cuvette. In parallel, standard methods were used to measure other chemical and physical characteristics of oat grain: protein content in the grain, its filminess, weight of 1000 grains. It was found that the husked samples formed a grain with a content of β-glucan in it about 3% and naked over 4%, while a noticeable advantage of the naked sample compared with the husked in the content of protein and fat in the grain was found. Cultivation of different oat samples in two geographical areas of Eastern Siberia for three years showed insignificant positive impact of climatic conditions of Khakassia on the content of β-glucans in grain, its size and filthiness and negative impact on fat and protein content. Comparison of the content of β-glucans and fat in oat grain of three varieties from two geographical points revealed a significant effect of the genotype (63.6 and 66.6%, respectively) and a slight influence of the point of cultivation, as well as the interaction of the genotype×point. The existence of strong negative links between the weight of 1000 grains and the content of β-glucans, fat or protein in the grain, as well as strong positive reliable links between the content of β-glucans and fat in the grain.
6
Shyamalee, H. A. P. A., and A. L. Ranawake. "Path coefficient analysis using traditional and improved rice genotypes for trait effect on grain yield ." Journal of the National Science Foundation of Sri Lanka 52, no. 1 (April 9, 2024): 93–102. http://dx.doi.org/10.4038/jnsfsr.v52i1.11649.
Анотація:
Accessions of traditional rice play a crucial role in preserving the genetic diversity of commercial rice. They contain specific and useful traits that can help to improve the overall yield, which cannot be achieved by relying solely on improved rice varieties. This is because traditional rice accessions display a wide range of morphological characteristics that contribute to their unique yield determinants. Fifty traditional and forty-five improved rice genotypes were evaluated for thirteen agronomic traits (days to 50% flowering, plant height, number of tillers per plant, number of effective tillers per plant, number of leaves per plant, panicle length, flag leaf length, flag leaf width, number of grains per panicle, filled grain percentage, 100-grain weight at maturity, grain length, and grain width) to understand the yield determination of traditional and improved rice genotypes. Path analysis was carried out using IBM SPSS AMOS statistical software to understand the difference in the direct and indirect effect of the studied parameters. The direct effect of effective tillers per plant (β = 0.519), filled grain percentage (β = 0.496), and hundred-seed weight (β = 0.403) on grain yield was high in improved rice varieties. In traditional rice accessions, the direct effect of effective tillers per plant (β = 0.746) and filled grain percentage (β = 0.395) on grain yield was high, but there was no direct effect of hundred seed weight. Filled grains per panicle recorded a moderate effect in both traditional (β =0.246) and improved (β = 0.266) rice genotypes. None of the studied parameters directly and negatively affected the yield of improved rice varieties. Still, several traits (flag leaf length, days to 50% flowering, panicle length, seed length, and seed width) negatively affected the yield of traditional rice accessions. The contributions of yield determinants in traditional rice accessions deviated substantially from those observed in improved rice varieties, highlighting the critical role of plant architecture in determining the final yield. Fertile tiller number, filled grain percentage and grains per panicle are possible traits that can be used in direct selection criteria for improved and traditional rice genotypes for high yield.
7
Yang, Lin, Jun Dong Wang, Si Ni Wang, Li Lin та Zheng Liu. "Microstructure and Kinetics of β-Mg17Al12 Phase Transformation for Warm Rolled AZ91 Magnesium Alloy". Materials Science Forum 747-748 (лютий 2013): 421–25. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.421.
Анотація:
The microstructure and the kinetics of β-Mg17Al12 phase transformation during annealing process for warm-rolled AZ91 magnesium alloy were investigated. The results showed that few twins were found in solid state AZ91 magnesium alloy after warm rolling, which provides energy for β-Mg17Al12 particles to nucleate and growth; the β-Mg17Al12 particles were prior to form at α-Mg, twin grains boundary and especially the place of high energy; by the annealing time extending, the quantity of β-Mg17Al12 particles increased. And combined with the experimental data and the JMAK equation, the fitting equation of Kinetics of β-Mg17Al12 phase transformation was built. During annealing process, the twin grains disappeared and the original bulky organization was replaced by recrystallization grain, while the grain refinement was obvious with the grain reduction to 20-60μm.
8
Shu, Dayu, Li Wang, Qiang Chen, Yi Yao, Minghui Li та Rui Wang. "Understanding the Role of β Recrystallization on β Microtexture Evolution in Hot Processing of a Near-β Titanium Alloy (Ti-10V-2Fe-3Al)". Metals 11, № 9 (3 вересня 2021): 1397. http://dx.doi.org/10.3390/met11091397.
Анотація:
The present study evaluated the β recrystallization behavior and deformation microtexture evolution of TB6 titanium alloy (Ti-10V-2Fe-3Al) taking place during isothermal compression. The hot deformation tests were carried out in the temperature range below the β phase transition temperature and spanned a wide strain rate range of 0.0001~1 s−1. Microstructure evolution on β phase, including its recrystallization behavior and microtexture formation, is sensitive to the strain rates, whereas the average grain size of equiaxed α phase exhibits a slight increase with the strain rate decreasing. Moreover, β recrystallization is not homogeneous among the prior β grains, and is characterized by: (I) enriched β sub-grains, (II) sporadically or chain-like distributed recrystallized β grains with a grain size far less than the prior β grains, and (III) wave-shaped β grain boundaries. The β recrystallization is inadequate and its orientation takes on the inheritance characteristic, which makes the β microtexture significant after deformation. At a lower strain rate, the high activity of the {11−2}<111> and {12−3}<111> slip systems induced the crystal rotation around <101>, but such crystal rotation did not destroy the Burgers orientation relationship (BOR), which could be accounted for by the generation of a strong microtexture of <001>//RD. The divergences on β recrystallization fraction, the operation of slip systems, and initial crystal orientations explain the different microtexture components with varied intensities under different deformation conditions.
9
Zhang, Shuzhi, Qibin Wang, Xing Cheng, Jianchao Han, Wanggang Zhang, Changjiang Zhang, and Jie Wu. "Static Recrystallization Behavior and Texture Evolution during Annealing in a Cold Rolling Beta Titanium Alloy Sheet." Metals 12, no. 6 (May 25, 2022): 899. http://dx.doi.org/10.3390/met12060899.
Анотація:
In this study, the cold rolling microstructure and static recrystallization mechanism of the high strength titanium alloy Ti-3.5Al-5Mo-6V-3Cr-2Sn-0.5Fe were systematically investigated. Results show that the cold rolling microstructure is mainly composed of the elongated deformed β grains containing micro-shear bands. After annealing at 815 °C for 2 min, the fine SRXed grains are observed, mainly concentrated in the micro-shear band, the grain boundary and the interior of the deformed grain. The sub-grain structure obtained by static recovery inside the deformed grain produces continuous SRX during the annealing treatment. Meanwhile, geometric and discontinued SRXed grains are also observed in the large deformed β grain and at the trigeminal grain boundaries, respectively. Many ultra-fine grains appear inside the micro-shear band, exhibiting a phenomenon of the micro-shear band assisting SRX. With the increase in the annealing holding time, the elongated β grains are significantly refined and the degree of recrystallization is continuously improved. In addition, the recrystallization behavior also results in a significant change in the fiber texture. With the extension of the annealing holding time, the rolling texture type evolves gradually, with the {111} <112> γ-fiber texture to weak α-fiber, γ-fiber, and Goss-fiber.
10
Hui, Qiong, Xiang Yi Xue, Hong Chao Kou, Min Jie Lai, Bin Tang та Jin Shan Li. "Phase Transformation and Microstructure Evolution in Near-β Ti-7333 Titanium Alloy during Aging". Materials Science Forum 747-748 (лютий 2013): 904–11. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.904.
Анотація:
A newly near-β titanium alloy Ti-7Mo-3Cr-3Nb-3Al (Ti-7333) was subjected to β phase solution treatment and ageing in the present work. The characteristics of α phase transformation in ageing treatment were studied. Results show that isothermal aging at a low temperature (350) will result in lots of ω particles with small size homogeneously distributing in the parent phase. These ω particles can act as nucleation sites for α phase and lead to the uniform precipitation of fine α phase within the β grain after further ageing treatment. However, when ageing at a higher temperature, the α phase tends to precipitate direct from the β matrix and the morphology of α phase is determined by the temperature and period of ageing treatment. After aging at 550 for 5min, acicular α phase precipitates in the β grains as well as along β grain boundaries and the size and quantity of α phase increase with the holding time. Note that Ti-7333 alloy has a quick ageing response. When aging at 700 for 1h, coarser α laths precipitate both on the grain boundary and within the grain. Increase the ageing temperature to 800, α phase precipitates within the β grain as short rod-like morphology. It is suggested that the driving force for α phase nucleation and the amount of defects in the intragranular decrease with the increasing of temperature, leading to the grain boundaries become the prior nucleation sites. Substantial α phase precipitate-free regions adjacent to β grain boundaries remained after ageing at 700 for 1h due to the rejection of β-stabilizer from coarse α lath on β grain boundaries. Aging at 800 for 1h resulted in pronounced continuous α-films along β grain boundaries.
11
Masuyama, Haruki, Tetsuya Matsunaga, Yoshiaki Toda, Tsutomu Ito, Masayuki Shimojo та Yoko Yamabe-Mitarai. "Microstructure Factor of Creep Behavior in Near-α Ti Alloy". Materials Science Forum 1016 (січень 2021): 1882–89. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1882.
Анотація:
Heat-resistant Ti-Al-Nb-Zr alloys, which don’t contain Sn, have been designed to obtain good oxidation resistance above 600 °C. In addition, to design Ti alloys with best balance of creep and fatigue properties, prior β grain size which affects fatigue properties and lamellar microstructure which affects creep properties were controlled by heat treatment. In the present study, the effect of microstructure on creep properties of one of the alloys, i.e., Ti-7.5Al-4Nb-4Zr alloy, with the bimodal (B), the lamellar structures in small prior β grains (LS), and the lamellar in large prior β grains (LL) were investigated at 600 °C. The creep deformation mechanism for each microstructure was a power-law creep. However, the creep life varied depending on the microstructures. The longest creep life was obtained in LS with prior β grain size of 90 μm and interlamellar spacing of approximately 10 μm, while the shortest creep life was obtained in LL with prior β grain size of 550 μm and fine interlamellar spacing of less than 2~3 μm. This suggests that creep life is more affected by interlamellar spacing than by prior β grain size.
12
Solovyeva, Nurguyana E., and Nikalay N. Novikov. "The brewing properties formation of barley grain depending on nutrition regime and phytoregulators application when growth on sod-podzolic soil." Butlerov Communications 59, no. 8 (August 31, 2019): 124–31. http://dx.doi.org/10.37952/roi-jbc-01/19-59-8-124.
Анотація:
In the field experiments with brewing barley, carried out on sod-podzolic medium-loamy soil, it has been found out, that the raising doses of nitrogen application increased grain productivity of barley plants (by 18-33%), grains protein content, α-amylases, сatalases and peroxidases activity, but decreased grain unit and β-amylases activity. In water deficit weather conditions (Hydrothermal coefficient of moisture on the G.T Selyaninov = 1-1.3) the raising doses of phosphorus and potassium (Р120, К120) increased the grain productivity of barley plants (by10-28%), the mass of 1000 grains, their germination ability and α-amylases activity, but decreased β-amylases, сatalases, peroxidases activity and grains protein content making it not more then normative level (12%). In 7-days germinated grains of barley harvested in the variants with raising doses of nitrogen it has been revealed increasing of α-amylases, proteases, catalases, peroxidases activity, but decreasing of β-amylases activity. In the variants with higher doses of phosphorus and potassium barley grains were formed, which observed on the 7th day of sprouting increased α-amylases and peroxidases activity and reduced activity of β-amylases. It has been revealed, that phytoregulators novosil and epin application enhanced grain productivity of barley plants (by 6-14%) and α-amylases activity in grains, but decreased β-amylases activity. In water deficit weather conditions novosil phytoregulator reduced grains protein content to normative level. In the variants with epin phytoregulators application barley grains were formed in which germination increased amylase and peroxidase activity, improving their ability to malting.
13
Kim, Young-Wook, Mamoru Mitomo та Guo-Dong Zhan. "Mechanism of grain growth in liquid-phase-sintered β–SiC". Journal of Materials Research 14, № 11 (листопад 1999): 4291–93. http://dx.doi.org/10.1557/jmr.1999.0581.
Анотація:
The mechanism for grain growth of β–SiC was investigated by annealing hot-pressed β–SiC–oxynitride glass (Y–Mg–Si–Al–O–N) ceramics at 1800 °C. An observed decrease in grain growth with increasing weight fraction of liquid confirms a diffusion-controlled growth mechanism in the system. The growth of nearly spherical β–SiC grains in the annealed specimen also supports the above conclusion.
14
Cui, Yi Min, Wei Wei Zheng, Feng Zhang та Ai Xue Sha. "Effect of β Annealing and near β Zone Hot Deformation on the Microstructure and Texture of TC18 Alloy". Materials Science Forum 849 (березень 2016): 226–31. http://dx.doi.org/10.4028/www.scientific.net/msf.849.226.
Анотація:
Forged TC18 alloy billets with strong <100> texture were selected to investigate the effects of β annealing and near β zone hot deformation on the microstructure and texture by means of optical microscopy, XRD and EBSD techniques. The results showed that the original <100> fiber texture can’t be eliminated through β annealing although completed static recrystallization happened during annealing. After deforming in near β phase zone, the microstructures were composed of elongated β grains. A lot of small angle boundaries were observed near the original β grain boundaries, indicating that dynamic recovery controlled the deformation. Dynamic recrystallization grains can only be seen at the original β grain boundary at the strain of 50%. <100>//TD and <111>//TD texture were generated during the near β zone hot deformation. Annealing at dual phase zone after hot deformation can effectively reduce the proportion of grains with <111> orientation, but the <100>//TD texture still existed.
15
Zhao, Xiang, Xin Li Wang, Dong Xue Li та Wen Bin Dai. "Orientation Correlation during α→β Up-Transformation Induced by Electric Current Pulses in a Cu-Zn Alloy". Materials Science Forum 783-786 (травень 2014): 2406–9. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.2406.
Анотація:
In this work, the orientation of the β variants within a single parent α grain on the α→β up-transformation induced by electric current pulses in a Cu-Zn alloy was investigated. Electron backscatter diffraction (EBSD) was used to determine the relationship between the α phase and the β variants. By EBSD analysis, it was found that crystallographic variant selection was observed not only across those prior α/α grain boundaries, but also within the α grain interior. Results revealed that the orientation relationship between the α phase and the β associated with nucleation from α phase was close to the Kurdjumov-Sachs (K-S) orientation relationship, which better described the orientation relationship for α nucleation within β grains.
16
Peltonen, Jari, Ari Virtanen, Jaakko Helenius, Juha Suopelto, Kari Kittilä та Esko Eloranta. "Determination of barley nitrogen status with chlorophyll meter for high β-amylase in grains". Agricultural and Food Science 4, № 5-6 (1 грудня 1995): 495–501. http://dx.doi.org/10.23986/afsci.72625.
Анотація:
The production of β-amylase is of great importance in two-rowed spring barley cv. Kymppi (Hordeum vulgare L.) in the Finland, where long-day conditions favour high enzyme activities. Nitrogen (N) fertilization of a crop is the main means of manipulating barley β-amylase activity for industrial purposes. In this study, leaf chlorophyll content determined with a portable chlorophyll meter (Minolta SPAD-502) in the field, was used to predict N availability of cv. Kymppi for β-amylase production. Critical chlorophyll meter readings (SPAD values) were calculated from data deriving from experiments with various N fertilizer levels using the Cate-Nelson procedure. According to the results of this study it can be stated that the critical SPAD values at pollination (i.e. pollen grains on well-developed stigmatic hairs, GS 52-58) are 37 SPAD units for grain yield and 41 SPAD units for β-amylase activity. The optimum grain yield occurred at 41 SPAD units and optimum P-amylase activity was reached at 45 SPAD units. Determination of leaf chlorophyll content using the chlorophyll meter led to more appropriate fertilizer application recommendations and subsequently increased β-amylase activity in grains. Grain protein concentration could be an effective diagnostic tool for post-harvest evaluation of grain β-amylase activity in cv. Kymppi.
17
Choe, Hye-Jeong, Jong Won, Yong-Taek Hyun, Ka Lim, and Seog-Young Yoon. "TiFe Precipitation Behavior and its Effect on Strengthening in Solution Heat-Treated Ti-5Al-3.5Fe During Isothermal Aging." Metals 8, no. 11 (October 26, 2018): 875. http://dx.doi.org/10.3390/met8110875.
Анотація:
We investigated the TiFe precipitation behavior of solution heat-treated Ti-5Al-3.5Fe during isothermal aging, quantified the effect of precipitation on strengthening by evaluating the hardness, and compared it to the effect of Ti3Al precipitation in Ti-6Al-4V. TiFe precipitates formed both at grain boundaries (GBs) and within the grain matrices. Phase transformation from the β to α phase also occurred during isothermal aging; this transformation generated lamellar interphase boundaries between the transformed α phase and remaining β phase in prior β grains. These interphase boundaries enabled the formation of in-grain TiFe precipitates by acting as a nucleation site. GB precipitation did not require prior β → α phase transformation to generate nucleation sites (i.e., interphase boundaries), so TiFe precipitation could occur immediately upon isothermal aging. Thus, GB precipitation proceeded more quickly than in-grain precipitation; as a result, precipitates were larger and more spherical at the GBs than in grains. The strengthening behavior exhibited by TiFe precipitation differed obviously from that caused by Ti3Al precipitation in Ti-6Al-4V because of its differing precipitation kinetics and related microstructural evolution.
18
Gao, Kun Yuan, Bo Li, Yu Sheng Ding, Hui Huang, Sheng Ping Wen, Xiao Lan Wu, and Zuo Ren Nie. "Investigations on the Hardness Distribution and Microstructure of Friction-Stir-Welded 6082 Aluminum Alloy." Materials Science Forum 993 (May 2020): 116–22. http://dx.doi.org/10.4028/www.scientific.net/msf.993.116.
Анотація:
The hardness and microstructure of friction stir welded (FSW) 6082 aluminum alloy joint were investigated by Vickers microhardness test, optical microscopy (OM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The hardness distribution is in a W shape, and from the base metal to the heat affected zone (HAZ) the hardness decreases from 103 HV to 72 HV, then gradually increases to 84 HV at the nugget zone (NZ). The grains of base metal (BM) are elongated and composed of a great quantity of low-angle grain boundaries. The nugget zon was of quite fine recrystallized grains. For the thermomechanical affected zone (TMAZ), the grain size is a little smaller than that of base metal and some low-angle grain boundaries remain. In the heat affected zone, the grain size was similar to that of the base metal. The β'' phase (Mg5Si6) and Al-Mn-Si particles are dispersed in the base metal. . In the heat affected zone, β'' phase transforms to β' phase (Mg9Si5). The hardness distribution in a W-shape was discussed on the basis of grain size, density of low-angle grain boundary and secondary phases.
19
Lu, Xin, Xiao Shan Ning, Wei Xu, He Ping Zhou, and Ke Xin Chen. "Study on Thermal Conductivity of Spark-Plasma-Sintered Silicon Nitride Ceramics." Key Engineering Materials 280-283 (February 2007): 1259–62. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.1259.
Анотація:
In the study, the spark plasma sintering (SPS) method was adopted to fabricate Si3N4 ceramics with Y2O3-MgO additives. Specimens with different grain dimensions, grain shapes, α/β phase ratios, densities were obtained by changing the heating rate and dwell time of SPS. The relationship between the microstructure and the thermal conductivity was studied. Results show that the heating rate and the dwell time have great influence on the microstructure and properties of Si3N4 ceramics. Both equiaxed and columnar β- Si3N4 grains are formed during sintering, but the thermal conductivity of Si3N4 ceramics is affected only by columnar grains. The thermal conductivity of the ceramics increases together with the formation and the growth of the β- Si3N4 columnar grains.
20
Fei, Yue, Xin Nan Wang, Zhi Shou Zhu, Jun Li, Guo Qiang Shang та Li Wei Zhu. "β Grain Growth Kinetics of a New Metastable β Titanium Alloy". Materials Science Forum 747-748 (лютий 2013): 844–49. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.844.
Анотація:
Ti-Mo-Nb-Cr-Al-Fe-Si alloy is a new metastable β titanium alloy with excellent combination of strength and ductility. The β grain-growth exponent and the activation energies for β grain growth for the investigated alloy at specified temperature were computed by the kinetic equations and the Arrhenius-type equation. The rate of β grain growth decreases with elongating solution treated time and increases with the increasing solution-treated temperature. The β grain-growth exponents, n, are 0.461, 0.464 and 0.469 at 1113, 1133 and 1153K, respectively. The β grain growth activation energy is determined to be 274 KJ/mol.
21
Luo, Zheng, Zhouming Tan, Yanguang Wei, Xuefei Cui, and Haiming Tao. "Effect of Solution Temperature on the Microstructure and Properties of TB10 Titanium Alloy Bars." Journal of Physics: Conference Series 2076, no. 1 (November 1, 2021): 012081. http://dx.doi.org/10.1088/1742-6596/2076/1/012081.
Анотація:
Abstract This paper studies the effect of solution temperature on the microstructure and mechanical properties of TB10 titanium alloy bars. The results show that the microstructure is composed of β phase and primary α phase (αp) when solution treatment is below the phase transition temperature. With the increase of the solution temperature, the β phase grain size in the microstructure increases, the thickness of the grain boundary decreases, and the number and size of the αp phase decrease, so that the strength of the alloy decreases and the plasticity increases. When the solution treatment temperature is 800°C, the reticulated grain boundary αp phase causes the plasticity to drop rapidly. When the solution treatment temperature is above the phase transition point, as the solution temperature rises, the β phase re-nucleates and grows, the grain size increases, the number of αp phase decreases. The super-cooled β phase grains induce martensite phenomenon due to stress, which eventually causes the strength and plasticity to decrease.
22
Dasgupta, Arup, Joysurya Basu, P. K. Parida, B. H. Vadavadagi, S. Saroja, M. Vijayalakshmi, and Tammana Jayakumar. "Texture, Grain Boundaries, Defects and Location of Substitutional Atoms in Cryo-Mechanically Processed Ti-5Ta-1.8Nb Alloy." Materials Science Forum 702-703 (December 2011): 131–34. http://dx.doi.org/10.4028/www.scientific.net/msf.702-703.131.
Анотація:
An α-β alloy (β~8% in the stress relieved condition) of Ti-5Ta-1.8Nb has been subjected to severe plastic deformation (SPD) by cryo-rolling. The grain size of α-Ti could be reduced significantly from ~ 8µm to 100 nm and less by cryo-rolling. Extensive plastic deformation leads to grain fragmentation through the formation of defect clusters. The fragmented grains exhibit deformation texture. High resolution transmission electron microscopy (HRTEM) confirmed the presence of low and high angle grain boundaries. The role of substitutional atoms (Ta, Nb) in producing lattice strains and altering the projected potential from the atomic columns has been discussed. Although, the minor phase, β (bcc-Ti) is evident in the starting alloy, it was not observed after SPD, possibly due to extended solid solution formation (Gibbs–Thomson effect) in the fine grains or due to the stress induced transformation of the α-Ti phase.
23
Paynter, Blakely H., та Stefan E. Harasymow. "Variation in grain β-glucan due to site, cultivar and nitrogen fertiliser in Western Australia". Crop and Pasture Science 61, № 12 (2010): 1017. http://dx.doi.org/10.1071/cp10146.
Анотація:
To adjust to projected changes in the future climate, maltsters are looking to reduce their water use. One option is to reduce the number of periods of water immersion during steeping from two to one. This might be possible if cultivars with very low grain β-glucan are used, as high β-glucan concentrations can restrict water penetration into the endosperm and the speed of germination. This study compared the grain β-glucan and various grain quality traits of nine two-row, Australian barley cultivars when grown at three sites with four rates of nitrogen (N) in Western Australia. Significant differences in grain β-glucan were found. Of the main factors, cultivar was found to have the largest effect on grain β-glucan followed by site, with N having the smallest effect. Grain β-glucan increased with increasing N application at two of the three sites. Not all cultivars responded similarly to N application. Grain with low β-glucan concentration generally had lower hectolitre weights, higher screenings, lower grain protein and was softer than grain with high grain β-glucan. There was no correlation between grain β-glucan and average grain weight, grain brightness or malt extract. The implication of these interactions and correlations in the breeding of very low grain β-glucan cultivars suited to single steep malting is discussed.
24
Wang, Moo-Chin, Nan-Chung Wu, Sheng Yang та Shaw-Bing Wen. "Effect of LiF addition on the phase transition of sinterable β-spodumene precursor powders prepared by a sol-gel process". Journal of Materials Research 17, № 8 (серпень 2002): 1960–68. http://dx.doi.org/10.1557/jmr.2002.0290.
Анотація:
β-Spodumene (Li2O · Al2O · 4SiO2, LAS4) precursor powders were obtained through a sol-gel process using Si(OC2H5)4, Al(OC4H9)3, and LiNO3 as starting materials and LiF as a sintering aid. X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy with a wavelength dispersive spectrometer, and electron diffraction analysis were utilized to study the phase transition of the β-spodumene glass–ceramics prepared from the gel-derived precursor powders with LiF additive. For the LAS4 precursor powders containing no LiF, the only crystalline phase obtained was β-spodumene. For the pellets containing less than 4.0 wt% LiF and sintered at 1050 °C for 5 h, the crystalline phases were β-spodumene solid solution and β-eucryptite (Li2O · Al2O3 · 2SiO2, LAS2) solid solution. When the LiF content was 5.0 wt% and the sintering process was carried out at 1050 °C for 5 h, the crystalline phases were β-spodumene solid solution, β-eucryptite solid solution (triclinic), and eucryptite [rhombohedral (hex.)]. When the LiF addition attains 3.0 wt%, the fully densified grains are formed, accompanied with an increase in grain size for LiF addition. At the triple junction of grain boundaries a second phase segregates which is identified to be β-spodumene solid solution. In the sintering period of LAS4 precursor powders with LiF additive, the grains converted to β-eucryptite solid solution and β-spodumene solid solution remains at the grain boundaries.
25
Dhaliwal, AS, and HL Sharma. "Changes in Some Carbohydrate Fractions and Some Related Enzymic Activities in Plump and Shrivelled Triticale and in Wheat Grains." Functional Plant Biology 13, no. 2 (1986): 249. http://dx.doi.org/10.1071/pp9860249.
Анотація:
Activities of α-amylase (EC 3.2.1.1), β-amylase (EC 3.2.1.2), soluble ADPglucose-starch synthase (EC 2.4.1.21), starch phosphorylase (EC 2.4.1.1), sucrose synthase (EC 2.4.1.13) and invertase (EC 3.2.1.26), and amounts of reducing sugars, total soluble sugars and starch, were studied in the developing grains of wheat and triticale lines. A triticale line (TL1) with shrivelled grains contained a low starch content, increased reducing and total soluble sugars during the final grain-filling period as well as a higher moisture at maturity than wheat and a plump-grain triticale line (TL2). The overall activities of soluble ADPglucose-starch synthase and starch phosphorylase remained lower and that of α- and β-amylases higher in TL1 than wheat and TL2 throughout grain development. The higher amylolytic activity retained during the final maturation period appears to be at least partly due to the higher moisture content of the grain in the triticale line TL1 with shrivelled grains.
26
Du, Sijie, Yang Song, Yiting He, Chunhua Wei, Rongyou Chen, Shubo Guo, Wei Liang, Shengyuan Lei, and Xiaohong Liu. "Evolution of Microstructure and Mechanical Properties of Ti-6Al-4V Alloy under Heat Treatment and Multi-Axial Forging." Materials 17, no. 5 (February 25, 2024): 1060. http://dx.doi.org/10.3390/ma17051060.
Анотація:
The mechanical properties of various Ti-6Al-4V alloys are influenced by their respective microstructures. This study generated an ultrafine-grain (UFG) Ti-6Al-4V alloy featuring bimodal grain distribution characteristics achieved through initial heat treatment, multi-axial forging (MF), and annealing. The study also extensively examined the evolution process of the alloy’s microstructure. By subjecting the materials to heat treatments at 900 °C with air cooling and 950 °C with air cooling, both materials were found to be consisted of primary α (αp) and transformed β (αs+β) regions with different proportions. Following MF, the sample treated at 900 °C displays a microstructure featuring UFGs of α+β surrounding larger micron-sized αp grains. On the other hand, the sample treated at 950 °C displays a microstructure distinguished by twisted αs lamellar and fragmented β grains surrounding larger micron-sized αp grains. Following annealing, no significant grain growth was observed in the sample. The geometrically necessary dislocations (GNDs) within the UFGs were eliminated, though some GNDs persisted within the αp grains. The samples undergoing the 900 °C heat treatment, MF, and subsequent annealing exhibited elevated strength (1280 MPa) and total elongation (10.7%). This investigation introduces a novel method for designing the microstructure of the Ti-6Al-4V alloy to achieve superior performance.
27
Zeng, Yu Ping, Naoki Kondo, Kiyoshi Hirao, Tatsuki Ohji, and Shuzo Kanzaki. "Fabrication and Properties of the Tape-Cast Si3N4 with Rod-Like Si3N4 Seed Addition." Key Engineering Materials 280-283 (February 2007): 1219–22. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.1219.
Анотація:
Silicon nitride ceramics with and without β-Si3N4 seed addition were prepared via tape casting nonaqueous ceramic slurries, laminating the green ceramic tapes, and gas pressure sintering the green bodies in nitrogen atmosphere. Lu2O3 and SiO2 were used as sintering additives. The results showed that the rod-like β-Si3N4 seed was helpful to enhance β-Si3N4 grain growth unidirectionally. The elongated grains grown from seeds were preferentially oriented parallel to the casting direction, resulting in anisotropic microstructure. When a stress was applied with along the grain alignment, the bending strength of the tape-cast Si3N4 with 3 wt% β-Si3N4 seed addition measured at 1500oC was 738 MPa, which was almost the same as the room temperature bending strength 739 MPa, and the fracture energy can be improved from 301 J/m2 at room temperature to 781 J/m2 at 1500oC. The large fracture energy and bending strength at 1500oC were attributable primarily to the unidirectional alignment fibrous grains and a high melting point grain boundary phase.
28
Rowenhorst, D., A. Lewis та G. Spanos. "Grain Boundary Curvature Analysis of β -Grains in Ti-21S". Microscopy and Microanalysis 15, S2 (липень 2009): 640–41. http://dx.doi.org/10.1017/s1431927609094082.
29
Garcia-Galan, Sergio, Gerardo Aramburo-Perez, Carlos González-Rivera, R. Herrera, and J. A. Juárez-Islas. "The Effect of Hot Rolling on Room Temperature Ductility of a NiAl Intermetallic Compound." Materials Science Forum 509 (March 2006): 69–74. http://dx.doi.org/10.4028/www.scientific.net/msf.509.69.
Анотація:
A Ni57Fe18Al25 alloy is produced by vacuum induction melting under an argon atmosphere and gravity cast into a copper chill mould. Ingots of 2 x 10 x 50 mm are re-heated at 1100 °C for 24 hours and hot rolled until a 25 % reduction is reached. Immediately, hot rolled plates are heat treated at 1100 °C for 1 hour and water cooled to room temperature. Microstructures of as cast, hot rolled and hot rolled plus heat treated specimens are characterized using scanning and transmission electron microscopy and x-ray diffraction. Specimens in the as-cast and hot rolled conditions show the presence of equiaxial and partially elongated β-grains, respectively, with the presence of a thin γ-phase decorating the grain boundaries. Hot rolled plus heat treated specimens have partially recrystallized β-grains with γ-phase and (Ni,Fe)3Al at the grain boundaries. The hot rolled specimens have a room temperature ductility of approximately 5 % in tensile testing. This enhancement in ductility is attributed to the modification of the β-grains by coexistence with a γ- phase along the grain boundaries.
30
Ran, Xing, Zhe Wang, Cheng Cheng Liu, Pei Jie Li, and Zhi Gang Lv. "Interrelationship of Fracture Mechanism and Microstructure of TC18 Titanium Alloy." Materials Science Forum 1071 (October 18, 2022): 38–45. http://dx.doi.org/10.4028/p-603ynr.
Анотація:
The scanning electron microscope (SEM) and optical microscope (OM) were used to study the deformation of TC18 titanium alloy microstructure at 881°C and 896°C. And the basket weave structure fracture mechanism was discussed. The results have been shown: during deformation at 881°C, the TC18 titanium alloy β grain size of about 305μm and the discontinuous grain boundary α phase along the β grain boundary were obtained. With the deformation temperature rising to 896°C, the β grain growth of 510μm and the continuous grain boundary α phase along the straight β grain boundary were obtained. The TC18 titanium alloy fracture toughness decreased from 77.8 MPa·m1/2 to 65.4 MPa·m1/2 as the rising of deformation temperature from 881°C to 896°C. The average β grain size is about 305μm and the discontinuous grain boundary α phase leads to the higher fracture toughness of TC18 titanium alloy forging. The fracture mode of fine β grain and discontinuous grain boundary α phase is the transgranular fracture, while the coarse β grain and continuous grain boundary α phase is the intergranular fracture.
31
Cho, Ken, Hirotaka Odo, Keisuke Okamoto, Hiroyuki Y. Yasuda, Hirotoyo Nakashima, Masao Takeyama та Takayoshi Nakano. "Improving the Tensile Properties of Additively Manufactured β-Containing TiAl Alloys via Microstructure Control Focusing on Cellular Precipitation Reaction". Crystals 11, № 7 (12 липня 2021): 809. http://dx.doi.org/10.3390/cryst11070809.
Анотація:
The effect of a two-step heat treatment on the microstructure and high-temperature tensile properties of β-containing Ti-44Al-4Cr (at%) alloys fabricated by electron beam powder bed fusion were examined by focusing on the morphology of α2/γ lamellar grains and β/γ cells precipitated at the lamellar grain boundaries by a cellular precipitation reaction. The alloys subjected to the first heat treatment step at 1573 K in the α + β two-phase region exhibit a non-equilibrium microstructure consisting of the α2/γ lamellar grains with a fine lamellar spacing and a β/γ duplex structure located at the grain boundaries. In the second step of heat treatment, i.e., aging at 1273 K in the β + γ two-phase region, the β/γ cells are discontinuously precipitated from the lamellar grain boundaries due to excess Cr supersaturation in the lamellae. The volume fraction of the cells and lamellar spacing increase with increasing aging time and affect the tensile properties of the alloys. The aged alloys exhibit higher strength and comparable elongation at 1023 K when compared to the as-built alloys. The strength of these alloys is strongly dependent on the volume fraction and lamellar spacing of the α2/γ lamellae. In addition, the morphology of the β/γ cells is also an important factor controlling the fracture mode and ductility of these alloys.
32
Qin, Dongyang, Huifang Liu та Yulong Li. "β Grain Size Inhomogeneity of Large Scale Ti-5Al-5V-5Mo-3Cr Alloy Bulk after Multi-Cycle and Multi-Axial Forging in α + β Field". Materials 16, № 4 (17 лютого 2023): 1692. http://dx.doi.org/10.3390/ma16041692.
Анотація:
In order to fabricate homogeneous large-scale Ti-5Al-5V-5Mo-3Cr (Ti-5553) alloy bulk with fine and equiaxial β grain, we performed a series of multi-axial α + β field forging with 62 forging cycles on the large-scale Ti-5553 billet by using 12.5 MN high-speed hydraulic press. The β-annealed microstructure was the starting microstructure of the billet. After the 6th forging cycle, β grain deformed dramatically, and the grain-boundary network developed within the irregular β grain. As the forging cycle increased to 44, the volume fraction of the fine and equiaxial β grain that is less than 20 μm, which is caused by dynamic recrystallization, increased gradually. However, the incomplete dynamic recrystallization region within the original β grain could not be eliminated. As the forging cycle further increased, the volume fraction of the fine and equiaxial β grain did not increase. In contrast, the abnormal grain growth of the β phase occurred during 50th~62nd forging cycle. Here, we attribute the formation of the incomplete dynamic recrystallization region and the abnormal grain growth of the β phase to the high deformation rate of the α + β forging. The refining behavior of β grain and the abnormal coursing β grain, which is found during the multi-cycle multi-axial forging of large-scale Ti-5553 alloy billet, are seldom reported in the isothermal compression of small-scale Ti-5553 alloy specimen. The findings of the paper are instructive for improving the sub-transus forging strategy that is used to fabricate the large-scale homogeneity Ti-5553 alloy billet with fine and equiaxial β grain.
33
Su, Tung-Huan, Nian-Hu Lu, Chih-Hsuan Chen, and Chuin-Shan Chen. "On the Decrease in Transformation Stress in a Bicrystal Cu-Al-Mn Shape-Memory Alloy during Cyclic Compressive Deformation." Materials 14, no. 16 (August 8, 2021): 4439. http://dx.doi.org/10.3390/ma14164439.
Анотація:
The evolution of the inhomogeneous distribution of the transformation stress (σs) and strain fields with an increasing number of cycles in two differently orientated grains is investigated for the first time using a combined technique of digital image correlation and data-driven identification. The theoretical transformation strains (εT) of these two grains with crystal orientations [5 3 26]β and [6 5 11]β along the loading direction are 10.1% and 7.1%, respectively. The grain with lower εT has a higher σs initially and a faster decrease in σs compared with the grain with higher εT. The results show that the grains with higher σs might trigger more dislocations during the martensite transformation, and thus result in greater residual strain and a larger decrease in σs during subsequent cycles. Grain boundary kinking in bicrystal induces an additional decrease in transformation stress. We conclude that a grain with crystal orientation that has high transformation strain and low transformation stress (with respect to loading direction) will exhibit stable transformation stress, and thus lead to higher functional performance in Cu-based shape memory alloys.
34
Cheng, Xiang Jun, Guo Qing Wu, and Jia Qi Zhao. "Quantification and Statistical Analysis of Microstructural Features in As-Cast Ti-6Al-4V Titanium Alloy." Materials Science Forum 747-748 (February 2013): 828–32. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.828.
Анотація:
Based on microstructure of as-cast Ti-6Al-4V titanium alloy, an image processing to simplify model of β grain size, α lamella space was developed and a quantitative statistical method of β grain size, α lamella space in two-phase titanium alloys was established, with which β grain size and α lamella space of as-cast Ti-6Al-4V titanium alloy with different plate thickness were analyzed. The relationship between β grain size, α lamellar space and cast plate thickness was discussed. The results show that β grain size and α lamellae thickness nearly linearly increase as plate thickness increasing. β grain size has normal distribution and with cast plate thickness increasing, the dispersion gets larger.
35
Zurak, Dora, Darko Grbeša, Marija Duvnjak, Goran Kiš, Tatjana Međimurec, and Kristina Kljak. "Carotenoid Content and Bioaccessibility in Commercial Maize Hybrids." Agriculture 11, no. 7 (June 24, 2021): 586. http://dx.doi.org/10.3390/agriculture11070586.
Анотація:
The objective of the present study was to determine the content and bioaccessibility of carotenoids in 104 maize hybrids available at the market. Lutein, zeaxanthin, α- and β-cryptoxanthin, and β-carotene were determined in whole grains and micelles produced during standardized INFOGEST digestibility analysis, and their bioaccessibility was calculated as the ratio of micellar and grain carotenoids. Tested hybrids varied in total carotenoid content, with 34% having total carotenoid content in the range of 15–20 µg/g dry matter (DM) and 41% in the range of 20–25 µg/g DM. The amount of bioaccessible carotenoids increased linearly (p < 0.05) with increasing content in the grain, and decreased among determined carotenoidsd in the order: lutein (52%) > zeaxanthin (43%) > β-carotene (43%) > α-cryptoxanthin (27%) > β-cryptoxanthin (26%). Bioaccessibility of lutein, zeaxanthin, and β-carotene decreased with increasing content in the grain (p < 0.05). On average, only 43% of the total carotenoids were bioaccessible in commercial maize hybrids tested, which should be considered when formulating an animal diet.
36
Tian, Ning, Wenjun Ye, Xiaoyun Song, and Songxiao Hui. "Microstructure and Texture Evolution during Superplastic Deformation of SP700 Titanium Alloy." Materials 15, no. 5 (February 28, 2022): 1808. http://dx.doi.org/10.3390/ma15051808.
Анотація:
The superplastic tensile test was carried out on SP700 (Ti-4.5Al-3V-2Mo-2Fe) titanium alloy sheet at 760 °C by the method of maximum m value, and the microstructure characteristics were investigated to understand the deformation mechanism. The results indicated that the examined alloy showed an extremely fine grain size of ~1.3 μm and an excellent superplasticity with fracture elongation of up to 3000%. The grain size and the volume fraction of the β phase increased as the strain increased, accompanied by the elements’ diffusion. The β-stabilizing elements (Mo, Fe, and V) were mainly dissolved within the β phase and diffused from α to β phase furthermore during deformation. The increase in strain leads to the accumulation of dislocations, which results in the increase in the proportion of low angle grain boundaries by 15%. As the deformation process, the crystal of α grains rotated, and the texture changed, accompanied by the accumulation of dislocations. The phase boundary (α/β) sliding accommodated by dislocation slip was the predominant mechanism for SP700 alloy during superplastic deformation.
37
Liu, Xiaoran, Todd Beck, Klodian Dhana, Pankaja Desai, Kristin R. Krueger, Christy C. Tangney, Thomas M. Holland, Puja Agarwal, Denis A. Evans, and Kumar B. Rajan. "Association of Whole Grain Consumption and Cognitive Decline." Neurology 101, no. 22 (November 28, 2023): e2277-e2287. http://dx.doi.org/10.1212/wnl.0000000000207938.
Анотація:
Background and Objectives To examine the association of whole grain consumption and longitudinal change in global cognition, perceptual speed, and episodic memory by different race/ethnicity. Methods We included 3,326 participants from the Chicago Health and Aging Project who responded to a Food Frequency Questionnaire (FFQ), with 2 or more cognitive assessments. Global cognition was assessed using a composite score of episodic memory, perceptual speed, and the Mini Mental State Examination (MMSE). Diet was assessed by a 144-item FFQ. Linear mixed-effects models were used to estimate the association of intakes of whole grains and cognitive decline. Results This study involved 3,326 participants (60.1% African American [AA], 63.7% female) with a mean age of 75 years at baseline and a mean follow-up of 6.1 years. Higher consumption of whole grains was associated with a slower rate of global cognitive decline. Among AA participants, those in the highest quintile of whole grain consumption had a slower rate of decline in global cognition (β = 0.024, 95% CI [0.008–0.039], p = 0.004), perceptual speed (β = 0.023, 95% CI [0.007–0.040], p = 0.005), and episodic memory (β = 0.028, 95% CI [0.005–0.050], p = 0.01) compared with those on the lowest quintile. Regarding the amount consumed, in AA participants, those who consumed >3 servings/d vs those who consumed <1 serving/d had a slower rate of decline in global cognition (β = 0.021, 95% CI [0.005–0.036], p = 0.0093). In White participants, with >3 servings/d, we found a suggestive association of whole grains with global cognitive decline when compared with those who consumed <1 serving/d (β = 0.025, 95% CI [−0.003 to 0.053], p = 0.08). Discussion Among AA participants, individuals with higher consumption of whole grains and more frequent consumption of whole grain had slower decline in global cognition, perceptual speed, and episodic memory. We did not see a similar trend in White adults.
38
Seo, Sun-Kyoung, Moon Gi Cho та Hyuck Mo Lee. "Crystal orientation of β-Sn grain in Ni(P)/Sn–0.5Cu/Cu and Ni(P)/Sn–1.8Ag/Cu joints". Journal of Materials Research 25, № 10 (жовтень 2010): 1950–57. http://dx.doi.org/10.1557/jmr.2010.0253.
Анотація:
Electron backscatter diffraction analysis was used to compare the crystal orientation of β-Sn grains in Ni(P)/Sn–0.5Cu/Cu and Ni(P)/Sn–1.8Ag/Cu joints before and after aging. In Ni(P)/solder/Cu joints, the solder composition (Cu versus Ag) significantly affects β-Sn grain orientation. In Ni(P)/Sn–0.5Cu/Cu, there are two types of small columnar grains grown from Ni(P) and Cu under bump metallurgy with a high-angle grain boundary crossing the joint closer to the Ni side; in contrast, Ni(P)/Sn–1.8Ag/Cu has large grains with low-angle boundaries. During thermal aging at 150 °C for 250 h, the Ni(P)/Sn–0.5Cu/Cu joints undergo a more significant microstructural change than the Ni(P)/Sn–1.8Ag/Cu joint. Additionally, obvious ledges developed along the high-angle grain boundary between the upper and lower areas in the Sn–0.5Cu joint.
39
Bleidere, Māra, Zaiga Jansone, Ilze Grunte, and Ida Jakobsone. "Biochemical Composition of Spring Barley Grain Pearled to Varying Degrees." Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. 71, no. 6 (December 1, 2017): 468–73. http://dx.doi.org/10.1515/prolas-2017-0082.
Анотація:
Abstract Differences in biochemical composition in dehulled and pearled grain samples affected by the various degrees of pearling were studied for spring barley (Hordeum vulgare L.). Twelve covered spring barley and two hulless genotypes were examined. Commercial samples of pearled barley were included for comparison. Covered barley grain samples were pearled using a small-scale barley pearler to obtain dehulled and pearled barley grain products with pearling percentage of 12% and 30%, respectively. Significant differences were observed in the chemical composition between dehulled grain and pearled grain. As the outer layers of the covered grain were removed to a greater degree by pearling, crude protein content, crude ash, total phenolic concentration and radical scavenging activity in the pearled grain significantly decreased (p < 0.001), while starch concentration increased, without changes in the β-glucans concentration. The concentration of phenolic compounds in the dehulled barley grain samples were 1.30 to 1.61 times higher than for pearled grains. There was a significant (p < 0.01) correlation determined among values of dehulled and pearled grain of different barley genotypes in crude protein, starch, and β-glucan content, but no relationship was found in total phenolic content and radical scavenging activity.
40
Liu, Jie, Shun Guo, Peng Zhang, Tao Ma, Zhuo Wang, Tongli Wu, Li Wang, and Kehong Wang. "A Novel Approach of Microstructure Refinement of TiAl in Laser Beam Welding." Metals 13, no. 1 (December 20, 2022): 7. http://dx.doi.org/10.3390/met13010007.
Анотація:
Grain refinement through borides is known to be suppressed when TiAl is welded with a laser beam. As β grains do not primarily nucleate on boride at a high cooling rate, a mixture of nitrogen and argon is applied as a protecting gas for the formation of TiN during solidification. The phase transformation is changed correspondingly from Liquid → Liquid + β → β → α + β → α + γ+ β → α2 + γ + B2 to Liquid → TiN + Liquid → β+ TiN → α + γ + TiN → α2 + γ+ TiN. It is found that β grains prefer to nucleate heterogeneously on the suspending TiN in the melt with orientation relationship {111}TiN// {110}β, leading to refined β grains. α2 colonies that were thus modified into fine non-dendritic grains. The effects of nitrogen as a shielding atmosphere on the microstructure evolution of TiAl are elaborately studied.
41
Cheng, Jun, Sen Yu, Jinshan Li, Jinyang Gai, Zhaoxin Du, Fuyu Dong, Jinyong Zhang та Xiaoyong Zhang. "Precipitation Behavior and Microstructural Evolution of α Phase during Hot Deformation in a Novel β-Air-Cooled Metastable β-Type Ti-B12 Alloy". Metals 12, № 5 (29 квітня 2022): 770. http://dx.doi.org/10.3390/met12050770.
Анотація:
The precipitation behavior and microstructural evolution of α phase in a novel metastable β-type Ti alloy, Ti-10Mo-6Zr-4Sn-3Nb (wt.%), during isothermal compression are investigated in this study through the use of SEM (scanning electron microscope), TEM (transmission electron microscope) (HRTEM) (high-resolution transmission electron microscopy) and EBSD techniques. The results show that some finer α precipitates are randomly distributed within the β matrix during hot deformation. The morphological characteristics of α precipitates are distinctly different from those of α precipitates during the same solution-plus-aging treatment. The volume fraction of α precipitate gradually increases with increased true strain. A large proportion of precipitated α phases are prone to be precipitated at HAGBs (high-angle grain boundaries) and LAGBs (low-angle grain boundaries) during isothermal deformation. On the contrary, only a small amount of spherical α phases is precipitated within the β grain. The crystallographic orientation relationships for most spherical α precipitates formed at LAGBs and within the β grains are similar, whereas the crystallographic orientation relationships for α precipitates at grain boundaries are significantly different. The precipitation behavior of α phase in the Ti-B12 alloy during hot compression is considerably influenced by the density of dislocations.
42
Ashwini, Ashwini, H. C. Sowmya, Prakash H. Kuchanur, R. V. Beladhadi, R. Lokesha, Ayyanagouda Patil, P. H. Zaidi, M. T. Vinayan, and K. Seetharam. "Genetic variability in heat tolerant maize (Zea mays L.) hybrids and their parents for yield and grain quality traits." International Journal of Agricultural and Applied Sciences 3, no. 2 (December 20, 2022): 50–54. http://dx.doi.org/10.52804/ijaas2022.329.
Анотація:
The present investigation was carried out to estimate genetic variability, heritability and GAM in inbred lines and hybrids. ANOVA indicated the availability of considerable variation for all the characters among inbred lines and hybrids except for ASI. PCV was higher than the GCV for all the characters. In inbred lines, important traits like plant height, number of grains per row, number of grains per cob, 1000-grain weight, grain yield per plant, dietary fibre, and β-carotene exhibited high PCV and GCV along with high heritability and GAM. Whereas, hybrids showed high values of PCV and GCV for ASI, phytic acid and high heritability coupled with high GAM were observed for traits like ASI, plant height, number of grains per row, number of grains per cob, shelling percentage, grain yield per plant, protein, dietary fibre, and β-carotene indicating the presence of variability in inbred lines and hybrids for these traits. Hence, simple selection for these traits in early generations for developing heat-tolerant maize lines can be practised.
43
Fei, Yue, Bin Tang, Hui Chang, Zhi Shou Zhu, Zhong Bo Zhou, Guo Qiang Shang, Jin Shan Li та Lian Zhou. "β Grain Growth Kinetics of Hot-Rolled TB-13 Alloy". Materials Science Forum 689 (червень 2011): 472–78. http://dx.doi.org/10.4028/www.scientific.net/msf.689.472.
Анотація:
A study on the kinetics of β grain growth of a fine-grained, hot-rolled TB-13 alloy was carried out by isochronal and isothermal solution treatments. The grain size of the as-rolled and as-solution-treated samples was determined by metallographic observation using the linear intercept method. The kinetic equations and the Arrhenius-type equation were applied to calculate the β grain growth exponent and the activation energy for β grain growth at special temperatures. The results showed that the β grain growth rate decreased with elongating solution treated time, but increased with increasing solution treated temperature. The β grain growth exponents (n) were 0.394, 0.403 and 0.406 during the solution treated temperatures at 1103K, 1153K and 1203K, respectively. The values of n increased with increasing solution treated temperature and the determined activation energy (Qm) for β grain growth after holding for 0.5h at 1103K-1203K was around 156KJ/mol.
44
Zhu, Jian, Yunna Xue, Xiaolan Bai, Xuehui Shen, Jianqun He, Yu Zhang та Anhai Li. "Preparation of In Situ Growth Multiscale β-Sialon Grain-Reinforced Al2O3-Based Composite Ceramic Tool Materials". Materials 16, № 6 (14 березня 2023): 2333. http://dx.doi.org/10.3390/ma16062333.
Анотація:
A kind of multiscale β-sialon grain-reinforced Al2O3 matrix composite ceramic tool material, named ASN, was prepared and studied. For the ASN, β-sialon (molecular formula: Si4Al2O2N6) was synthesized in situ by a hot-pressing and solid-solution reaction process. A total of six samples were prepared at varying sintering temperatures and holding times under vacuum conditions. The solid solution reaction mechanism of β-sialon, the phase composition, mechanical properties, microstructure, and strengthening and toughening mechanisms of the composite ASN were investigated. As a result, within the experimental parameters, an optimal ASN tool material was obtained under a pressure of 32 MPa and at a temperature of 1550 °C for 20 min. The tested mechanical properties of the optimal sample were as follows: flexural strength 997 ± 59 MPa, fracture toughness 6.4 ± 0.3 MPa·m1/2, Vickers hardness 18.2 ± 0.4 GPa, and relative density 98.1 ± 0.2%. According to crystal defect theory, the solid solution reaction mechanism of in-situ-synthesized β-sialon in an Al2O3 matrix involves a double mechanism of unequivalence (or hetero-valence) and interstitial filling. The multiscale β-sialon grains mainly consisted of four grains, which were elongated β-sialon grains with a diameter of 0.3–0.4 μm and an aspect ratio of 6–9, elongated β-sialon grains with a diameter of 70 nm and an aspect ratio of 10, β-sialon whiskers with a diameter of 0.2 μm and an aspect ratio of 12–15, and intragranular β-sialon whiskers with a diameter of 70 nm. The mechanical properties were improved due to strengthening and toughening mechanisms, such as mixed structure mode (intergranular and transgranular), elongated grain pullout, interface bonding, crack reflection, pinning, and bridging.
45
Zhang, Ju Mei, Zhi Hu Wang, Bai Ling Jiang, Zi Shan Chen та Li Bin Niu. "Influence of Annealing Treatment on Precipitation of β-Mg17Al12 Phase of AZ80 Magnesium Alloy". Advanced Materials Research 476-478 (лютий 2012): 55–58. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.55.
Анотація:
The microstructure and element distribution of AZ80 magnesium alloy as-cast and after annealing treatment were studied by OM, SEM, XRD, EDS and TEM. The results show that the coarse divorced eutectic phase distributed along the grain boundary dissolve into Mg matrix during the isothermal process at 415°C for 24h. During the cooling process of annealing treatment, the lameller-shape β-Mg17Al12 nucleated preferentially in the grain near the boundary, then grows towards the neighbor grains with longitudinal direction, which precipitated from magnesium solid solution as perlite-type precipitation. When cooled to room temperature, the lameller-shape β-Mg17Al12 was uniformly distributed in the matrix, and the lamellar spacing inside β phase is about 1-2μm.
46
Satarova, T. M., V. V. Semenova, J. Zhang, H. Jin, B. V. Dzubetskii та V. Y. Cherchel. "Differentiation of maize breeding samples by β-carotene content". Regulatory Mechanisms in Biosystems 10, № 1 (23 квітня 2019): 63–68. http://dx.doi.org/10.15421/021910.
Анотація:
Plant carotenoids are important micronutrients in the diet of humans and animals, since they act as precursors for the synthesis of vitamin A in animal cells. The most effective precursor to the vitamin A biosynthesis is β-carotene. Increasing the β-carotene content in maize grain as an important feed and food crop is an urgent task for plant selection. The purpose of this work was to differentiate maize breeding samples from the Dnipro breeding program by the β-carotene content in mature grain. Maize grain of 18 inbreds harvested in 2015 and 5 inbreds harvested in 2016 was researched. Determination of β-carotene content in matured dry grain was carried out after petroleum ether extraction and ultra performance liquid chromatography (UPLC) in the mobile phase of methanol/acetonitrile. The β-carotene content in the grain of genotypes from the Dnipro breeding program was on average 1.020 mg/kg for inbreds grown in 2015, and 0.672 mg/kg for inbreds grown in 2016. These values correspond to the β-carotene content in the grain of the majority of genotypes from world breeding programs selected by methods of classical selection. The inbred DKV3262 with white grain had the smallest content of β-carotene (0.076 mg/kg), while the yellow-coloured line DKD9066 had the highest one (2.146 mg/kg). The variation in the grain β-carotene content in different years of maize cultivation was noted. Inbreds of flint and semident maize showed the general tendency to increase the β-carotene content in grain compared with dent ones. The distribution of the studied inbreds on germplasm types showed the significant variation of β-carotene content in grain and the incidence of relatively high values in all germplasms analyzed. Inbreds containing more than 1.5 mg of β-carotene per 1 kg of grain, DK239, DK206A, DK212, DKD9066 and DKE-1, are emphasized as promising for the selection to increase the content of valuable micronutrients.
47
Kuwano, Noriyuki, Marina Binti Lias, Nur Azmah Binti Nordin, Youhei Soejima, and Ahmad Rafiqan bin Nayan. "Preliminary Study on Deformation and Recrystallization Behavior of Pure Tin for Mitigation of Whisker Growth." Solid State Phenomena 273 (April 2018): 107–11. http://dx.doi.org/10.4028/www.scientific.net/ssp.273.107.
Анотація:
Since the mechanism of Sn-whisker growth is closely related with the behavior of deformation and recrystallization, understanding of the behavior is very important to establish the measure for mitigation of whisker growth. In this work, microstructural changes after heavy deformation by scratching were characterized by EBSD for a single crystal of β-Sn, and the following results were obtained. Three types of crystal grains appear immediately after the deformation; small grains in aggregation, large serrated grains and rim-grains. The small grains are considered to be formed by dynamic recrystallization. They continue to grow at a room temperature over a lengthy period of time. The large grain has a certain crystallographic relationship with the matrix where <100> axes of the large grain and the matrix are almost parallel to each other. The serrated boundaries of large grain are so stable that the large grain does not show a grain growth process. The stable boundary is considered to promote a continuous growth of whiskers.
48
Tong, Jian Feng, Da Ming Cheng, Bao Wei Li, Huang Hao Ling, and Wang Ling. "Microstructure and Performance of the Hot-Pressed Silicon Nitride Ceramics with Lu2O3 Additives." Key Engineering Materials 434-435 (March 2010): 37–41. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.37.
Анотація:
The influence of Lu2O3 on phase transformation and seeds morphology was investigated. The result showed that the β-Si3N4 seeds with up to 95% β phase content could be obtained with 2wt% Lu2O3 as the additive content under 1750°C for two hours. The microstructure and mechanical properties of hot-pressed Si3N4 ceramics, using 9wt.% of Lu2O3• additives were investigated by the means of MTS measurements and Vickers indentation crack size measurements, as well as XRD and SEM. It was known that the high fracture toughness of Si3N4 ceramics was attributed to the rodlike morphology of β-Si3N4 grains. And the reinforcement effect and mechanism of β-Si3N4 seed were studied. It was found that the grain size and its distribution influence the property and microstructure of Si3N4 ceramics, namely, the relative narrow distribution of grain diameter in some extent and relative wide range of bimodal distribution of grain aspect ratio could improve the property of Si3N4 ceramics. The improvement in the fracture toughness with the amount of additive was mainly attributed to elongated grain growth during the sintering process.The high temperature properties of self-reinforced Si3N4 with different additives were studied. By this method, self-reinforced Si3N4 ceramics with an increment of 10~20 percent of fracture toughness was successfully fabricated.
49
Pilchak, A. L., S. Srivatsa, N. C. Levkulich, V. Sinha, E. J. Payton, and S. L. Semiatin. "Characterizing and Modeling the Precursors to Coarse Grain Formation during Beta-Annealing of Ti-6Al-4V." MATEC Web of Conferences 321 (2020): 12007. http://dx.doi.org/10.1051/matecconf/202032112007.
Анотація:
Coarse prior β grains exceeding 3 mm in diameter have been sporadically observed following β annealing of α+β forged titanium alloys. Recent work has shown that the occurrence of coarse grains may be due in part to the stabilization of a {001}<110> texture during hot working that was further enhanced in intensity at the expense of other texture components during the early stages of β annealing. With the majority of the material comprised of low misorientation subgrains of a single texture component, the nuclei for coarse grains was the minority fraction of grains that were highly misoriented, and therefore had boundaries with higher energy and mobility, compared to the average grain. In this work, Ti-6Al-4V bar was side-pressed to various reductions in the α+β phase field to further investigate the role of texture and the effects of strain, strain-path, and deformation heating on the propensity to form abnormally large grains during β-annealing. The experiments were interpreted in the context of a continuum finite element model and viscoplastic self-consistent crystal plasticity simulations. Based on the results from experiment and modeling, we make recommendations with respect to the α+β forging process to avoid the occurrence of excessively coarse β grains.
50
Majore, Kristīne, Vita Šterna, Māra Bleidere, Sanita Reidzāne, and Inga Ciproviča. "In-Vitro Study on Fermentation Characteristics of Different Hulless Barley Cultivar Flakes." Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. 75, no. 6 (December 1, 2021): 438–43. http://dx.doi.org/10.2478/prolas-2021-0065.
Анотація:
Abstract Barley (Hordium vulgare L.) grain is an important food ingredient due to the presence of essential compounds like β-glucans, proteins, resistant starch, phenolic compounds etc. β-glucans are able to lower cholesterol level in blood plasma and the glycaemic index, to enhance lipid metabolism and to reduce the risk of colon cancer. Hulless barley cultivars are more suitable to the human diet, because the hulls can be easily removed, as well as minimal grain processing in food production contributes to the full benefit of the whole grain. Several studies show that hulless grains have a higher digestible energy, and they have higher protein content compared to hulled grains. Different cultivars have unique composition and physical properties. The hulless barley cultivars are less studied than hulled barley and oats. The aim of this study was to evaluate the fermentation characteristics of flakes of different hulless barley cultivars in vitro and to analyse the fermentation pattern of β-glucans and proteins. Samples of six hulless barley cultivar flakes with different β-glucan (4.17–6.59%), soluble dietary fibre (18.1–32.0%) and resistant starch (0.74–10.65%) content were boiled in water 10 min, and the obtained porridge samples were treated under in vitro fementation conditions. The concentration of fermented porridge solids as well as β-glucans and proteins was measured. The concentration of undigested solids varied from 38.3 to 61.0% depending on barley cultivar. The concentration of protein was not significantly changed, but β-glucan concentration was significantly decreased after in vitro digestion comparing to indigestible samples.