Academic literature on the topic 'Grain β'
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Journal articles on the topic "Grain β":
1
Zhang, Xue, Yi Chen, Feng Shou Zhang, Jun Ting Yang, Yun Jin Lai, Hong Chao Kou, Jin Shan Li, and Lian Zhou. "Microstructural Evolution and Precipitation Mechanism of α-Phase in Ti-55531 Alloy Aged at High Temperature." Materials Science Forum 747-748 (February 2013): 912–18. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.912.
Abstract:
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.
Abstract:
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, and Yu Hui Wang. "Recovery and Recrystallization Behavior of Large Sized β Phase Grains in TC18 Titanium Alloy during Annealing Process." Materials Science Forum 817 (April 2015): 263–67. http://dx.doi.org/10.4028/www.scientific.net/msf.817.263.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
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.
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Yang, Lin, Jun Dong Wang, Si Ni Wang, Li Lin, and Zheng Liu. "Microstructure and Kinetics of β-Mg17Al12 Phase Transformation for Warm Rolled AZ91 Magnesium Alloy." Materials Science Forum 747-748 (February 2013): 421–25. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.421.
Abstract:
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.
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Shu, Dayu, Li Wang, Qiang Chen, Yi Yao, Minghui Li, and 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, no. 9 (September 3, 2021): 1397. http://dx.doi.org/10.3390/met11091397.
Abstract:
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.
Abstract:
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.
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Hui, Qiong, Xiang Yi Xue, Hong Chao Kou, Min Jie Lai, Bin Tang, and Jin Shan Li. "Phase Transformation and Microstructure Evolution in Near-β Ti-7333 Titanium Alloy during Aging." Materials Science Forum 747-748 (February 2013): 904–11. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.904.
Abstract:
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.
Dissertations / Theses on the topic "Grain β":
1
Olsson, Mirja. "Chemical stability of grain boundariesin β-tricalcium phosphate ceramics : β-TCP as bone substitute material." Thesis, Uppsala universitet, Institutionen för kemi - Ångström, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173285.
Abstract:
β – Tricalcium phosphate (β-TCP, Ca3(PO4)2) is a commonly used bone substitute material due to its biocompatibility and resorption. This study focused on the production of almost fully dense β-TCP ceramics with varying degrees of impurities (Ca/PO4 ratio, addition of 5% Mg). Three methods were used to produce the β-TCP ceramics, uniaxial pressing, slip-casting and isostatic pressing. In this study the isostatic pressing and sintering at 1150ºC for 20h and 15min, resulted in the densest β-TCP ceramics (97.7-99.2%). No significant differences of grain size and density could be detected between the samples produced with various compositions. These isostatically pressed samples sintered at 1150ºC were then dissolved in 0.08M aceticacid solution to simulate the in vivo resorption. It was found that the samples containing extra Mg dissolved slower. Attempts to determine the chemical composition of the grain boundaries were made without success. However, SEM observations of partly dissolved β-TCP ceramics revealed that the grain boundaries dissolved faster than the grains. The study was performed at the RMS foundation in Switzerland.
2
Sehgal, Blossom. "Stored-grain insect management with insecticides: evaluation of empty- bin and grain treatments against insects collected from Kansas farms." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/15528.
Abstract:
Master of ScienceDepartment of Grain Science and Industry
Bhadriraju Subramanyam
The insecticides, β-cyfluthrin and chlorpyrifos-methyl plus deltamethrin, are approved in the United States for treating empty bin surfaces. Chlorpyrifos-methyl plus deltamethrin and spinosad insecticides are approved for direct treatment of wheat. The efficacy of commercial formulations of β-cyfluthrin and chlorpyrifos-methyl plus deltamethrin at labeled rates was evaluated against adults of 16 field strains of the red flour beetle, Tribolium castaneum (Herbst); seven strains of sawtoothed grain beetle, Oryzaephilus surinamensis (L.); and two strains of the lesser grain borer, Rhyzopertha dominica (F.). Concrete arenas in plastic Petri dishes (9 cm diameter) were used to simulate the concrete floor of empty bins. The time for ~100% knockdown and mortality of adults of laboratory strains of the three species was first established by exposing them to insecticide-treated concrete surfaces for 1 to 24 h. Adults of field strains of each species were exposed to specific established insecticide-time combinations. Mortality of all species was lower than knockdown, suggesting recovery after seven days when placed on food. Chlorpyrifos-methyl plus deltamethrin did not control all R. dominica and most O. ]surinamensis field strains. β-cyfluthrin was extremely effective against R. dominica but ineffective against T. castaneum and O. surinamensis field strains, even at four times the high labeled rate. Field strains of R. dominica were highly susceptible to spinosad and chlorpyrifos-methyl plus deltamethrin at labeled rates on hard red winter wheat. Strains of T. castaneum and O. surinamensis were susceptible only to the latter insecticide. Dose-response tests with spinosad on the two least susceptible field strains of each species showed the lethal dose for 99% mortality (LD[subscript]99) for T. castaneum and R. dominica field strains were similar to that of the corresponding laboratory strains. Corresponding values for the two O. surinamensis field strains were significantly greater (~6 times) than the laboratory strain. The effective dose for progeny reduction (ED[subscript]99) of only one R. dominica field strain was significantly greater (~2 times) than that of the laboratory strain. The baseline susceptibility data of field strains of three insect species to spinosad will be useful for monitoring resistance development once this product is commercially released as a grain protectant.
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Giroud, Tiphaine. "Impact de la structure β sur le comportement mécanique de l’alliage de titane β-métastable Ti-10V-2Fe-3Al." Electronic Thesis or Diss., Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2024. http://www.theses.fr/2024ESMA0003.
Abstract:
Les alliages de titane β-métastable sont utilisés dans le domaine aéronautique pour leur résistance spécifique élevée. En particulier, l’alliage Ti-10V-2Fe-3Al est employé pour certains composants de trains d’atterrissage. Un enjeu important pour l’utilisation de ces alliages est la compréhension de l’anisotropie et de la variabilité considérable des propriétés mécaniques en traction, notamment concernant la ductilité. Ces alliages présentent une fraction élevée de phase β à température ambiante(environ 40 %) et son implication dans l’anisotropie des propriétés mécaniques a été relativement peu étudiée. Ce travail de thèse s’est donc focalisé sur la compréhension de l’impact respectif des textures morphologiques et cristallographiques de la phase β sur les propriétés mécaniques en traction de l’alliage Ti-10V-2Fe-3Al. Des essais de traction monotone à température ambiante avec différentes directions de prélèvement ont permis de mettre en évidence le rôle non négligeable de la phase βsur l’anisotropie du comportement mécanique du Ti-10V-2Fe-3Al. Un suivi de la déformation réalisé in-situ sous microscope optique a permis de montrer que la localisation de la déformation est gouvernée par l’anisotropie élastique et l’orientation morphologique de la phase β. La répartition de la déformation est primordiale à prendre en compte car elle est corrélée à l’allongement à rupture, qui dépend également des mécanismes d’endommagement actifs. En particulier, les orientations morphologique et cristallographique du grain β sont déterminants vis-à-vis du mécanisme d’endommagement, trans- ou intergranulaire. L'influence du volume sollicité sur la variabilité des propriétés mécaniques a également été considérée, étant donné la taille millimétrique des grains β. L’augmentation du volume sollicité entraine une homogénéisation de la déformation et améliore la résistance à l’endommagement à l’échelle de l’éprouvette. Cependant, l’augmentation du volume sollicité entraine également une augmentation de la probabilité de contenir des configurations de microstructures critiques, responsables de la rupture des éprouvettes. Il existe ainsi une relation complexe entre les dimensions des éprouvettes et la ductilitéHigh strength metastable β titanium alloys are increasingly employed in the aircraft industry due to their outstanding strength to-weight ratio. In particular, the Ti-10V-2Fe-3Al alloy has been successfully used in landing gears of modern aircrafts. A major challenge for their use is to understand the anisotropy and variability of tensile properties, particularly for ductility. These alloys have a high β-phase fraction at room temperature (around 40%), and its involvement in the anisotropy of mechanical properties has been relatively understudied. This thesis focused on understanding the respective impact of β-phase morphological and crystallographic textures on the tensile properties of the Ti-10V-2Fe-3Al alloy. Monotonic tensile tests at room temperature with multiple sampling directions highlighted the non-negligible role of the β-phase on the anisotropy of the mechanical behavior. In-situ DIC during tensile tests under an optical microscope has shown that strain localization is governed by elastic anisotropy and the morphological orientation of the β-phase. Strain distribution is correlated with elongation, which also depends on active damage mechanisms. In particular, the morphological and crystallographic orientations of the β-grain are decisive for the damage mechanism, whether trans- or inter-granular. The influence of stressed volume on the variability of mechanical properties was also considered due to the millimetric size of β-grains. Increasing the stressed volume leads to strain homogenization and improves damage resistance at the specimen scale. However, increasing the stressed volume also increases the probability of containing critical microstructure configurations,responsible for specimen failure. There is a complex relationship between specimen size and ductility
4
Salib, Matthieu. "Étude cinétique et cristallographique de la précipitation de la phase α aux joints de grains β/β dans un alliage de titane." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0042/document.
Abstract:
Ce travail de thèse porte sur la formation et l’évolution des microstructures et microtextures des alliages de titane associées à la précipitation de la phase α aux JDGs β/β. L’alliage β-métastable Ti17 a été utilisé comme alliage modèle de par son aptitude à figer sa microstructure haute température, permettant de conserver la phase parente non transformée. De nombreuses analyses cristallographiques EBSD 2D et quelques analyses 3D ont été réalisées pour des microstructures formées sous diverses sollicitations thermiques (transformation en conditions isotherme (TI) ou refroidissement continu (RC)) et thermomécaniques (déformation de la phase parente puis TI ou RC). L’étude statistique automatisée des microtextures a été menée à partir de données EBSD en utilisant un algorithme spécifique conduisant aux mesures d’orientations de variants et à des grandeurs représentatives de la microtexture. Un lien étroit entre la cinétique de germination croissance de la phase α et le développement de la microtexture est mis en évidence, alors que ce paramètre est souvent négligé dans les travaux de la littérature. De plus, l’étude de différents critères de sélection de variants (SV) a conduit à montrer que la SV était fréquente pour les premiers grains formés. Ces premiers grains ont des conditions de germination plus favorables ; le variant choisi est celui qui minimise l’écart à la ROB avec les deux grains β. Autrement dit, l’énergie d’interface et surtout l’énergie élastique associée à la formation de ce variant sont minimales. Les conditions cristallographiques de formation des colonies de lamelles sont également étudiées et discutéesThis work focuses on the formation and the evolution of microstructure and microtexture associated with the α phase precipitation at β/β GBs in titanium alloys. A β-metastable alloy (Ti17) has been studied, because the high temperature microstructure is frozen by a rapid quench and the untransformed parent phase remains. Numerous 2D EBSD analyses and some 3D analyses have been carried out after transformation and under various thermal and thermo-mechanical treatments (isothermal conditions and continuous cooling (CC) without and with prior deformation of the parent phase). One great originality of this study is the automated statistical approach used to characterize the microtexture from EBSD data. An algorithm has been specifically developed in order to get the variants orientation as well as different representative data characterizing the microtexture. We have identified the link between the nucleation/growth kinetics of α phase and the microtexture development, a relationship that is often neglected in the literature, where one usually associates the microtexture only to the variant selection and to the initial β texture. The occurrence of variants selection (VS) has been performed considering different VS criteria; it has been shown that VS is very active for the first grains formed. These grains have the most favorable nucleation conditions. The variant selected is the one that minimizes the deviation to the Burgers Orientation Relationship with both β grains; i.e. the one for which interfacial energy and especially the elastic energy associated to its formation are minimized. Moreover, the crystallographic conditions of α colonies formation are studied and discussed
5
Matthies, Olga [Verfasser], Juri [Akademischer Betreuer] Grin, Miroslav [Akademischer Betreuer] Kohout, Juri [Gutachter] Grin, and Gotthard [Gutachter] Seifert. "Topological analysis of the cd → β-Sn phase transition of group 14 elements / Olga Matthies ; Gutachter: Juri Grin, Gotthard Seifert ; Juri Grin, Miroslav Kohout." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://d-nb.info/1151817023/34.
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Bugli, Beatrice. "Caratterizzazione di olio ottenuto dalla co-frangitura di olive e grani di pepe." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Abstract:
L’obiettivo di questa tesi è stato volto alla produzione di un olio naturalmente ricco in antiossidanti tipici di due matrici vegetali comunemente usate dai consumatori: olive e pepe. Attraverso la co-frangitura, un processo a basso impatto tecnologico sulle matrici, è stato possibile estrarre composti chimici peculiari della spezia e trasferirli all’olio, ottenendo così due tipologie di olio co-franto: un olio co-franto con grani di pepe decorticati e uno co-franto con grani di pepe non decorticati.
La caratterizzazione eseguita a carico degli oli ha interessato l’analisi dei composti volatili trasferiti dal pepe all’olio, tra i quali i più interessanti sono risultati essere il β-pinene, il cariofillene, il δ-3-carene, il β-fellandrene e il limonene, che infatti sono tipici composti d’aroma del pepe. Inoltre, è stata eseguita un’analisi spettrofotometrica al fine di indagare la frazione carotenica (b-carotene), e un’analisi sensoriale descrittiva (olfattiva e visiva), con il fine di indagare, anche sotto questo aspetto, le differenze tra un olio franto da olive tal quali e i due oli co-franti con il pepe. In fase di valutazione sensoriale gli oli co-franti sono stati descritti con sentori di pepe, di legno e con note balsamiche. Attraverso i dati ottenuti si è concluso come l’olio fosse caratterizzato da note sensoriali apprezzabili, sia alla vista che all’olfatto, dovute alla presenza simultanea di composti aromatici del pepe e delle olive; al contempo, si è visto come l’olio ottenuto da co-frangitura con pepe non decorticato, risultasse nettamente più ricco in composti aromatici e in pigmenti carotenici e clorofillici rispetto all’olio co-franto con pepe decorticato, a dimostrazione del fatto che la fase di decorticatura del pepe porta all’eliminazione di una parte in realtà ricca di molecole bioattive, che invece potrebbe costituire un sottoprodotto da valorizzare.
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Trégo, Gwenaël. "Comportement en fluage à haute température dans le domaine biphasé (α + β) de l'alliage M5®." Phd thesis, Paris, ENMP, 2011. https://pastel.hal.science/pastel-00688207.
Abstract:
Le comportement en fluage isotherme de l'alliage M5® a été étudié à haute température dans le domaine biphasé (α+β). Une première approche consiste en l'identification des lois de fluage des phases α et β dans leur domaine monophasé respectif puis en l'extrapolation de ces lois dans le domaine biphasé. Cette approche ne permet malheureusement pas de reproduire le comportement expérimental. Une amélioration de ce modèle est développée dans cette étude en prenant en compte deux effets microstructuraux : (i) la taille de grains : des tailles de grains spécifiques contrôlées ont été obtenues en appliquant des traitements thermo-mécaniques au matériau. Des essais de fluage dans les domaines quasi-α et quasi-β ont ainsi mis en évidence un fort effet de la taille de grains, en particulier dans le régime de fluage diffusionnel. (ii) le contraste micro-chimique entre les phases α et β dans le domaine biphasé : d'après des calculs thermodynamiques et des analyses microstructurales, la phase β est enrichie en Nb et appauvrie en O (inversement pour la phase α). Des essais de fluage ont alors été mis en œuvre sur des alliages Zr-Nb-O dont les teneurs en Nb et O sont représentatives de chaque phase dans le domaine biphasé. Cette base expérimentale a permis de d'identifier de nouvelles lois de fluage pour les phases α et β. Ces lois ont été ensuite implémentées dans un modèle éléments finis afin de simuler le comportement du matériau biphasé. La morphologie 3D des phases (en particulier la germination de la phase β aux joints de grains α) est introduite explicitement dans les simulations afin de mettre en évidence son effet sur le comportement macroscopique. M5® est une marque déposée d'AREVA NPThe isothermal steady-state creep behavior of a M5® thin sheet alloy in a vacuum environment was investigated in the (α+β) temperature, low-stress (1-10MPa) range. To this aim, the simplest approach consists in identifying α and β creep flow rules in their respective single-phase temperature ranges and extrapolating them in the two-phase domain. However, the (α+β) experimental behavior may fall outside any bounds calculated using such creep flow data. Here, the model was improved for each phase by considering two microstructural effects: (i) Grain size: Thermo-mechanical treatments applied on the material yielded various controlled grain-size distributions. Creep tests in near-α and near-β ranges evidenced a strong grain-size effect, especially in the diffusional creep regime. (ii) Chemical contrast between the two phases in the (α+β) range: From thermodynamic calculations and microstructural investigations, the β phase is enriched in Nb and depleted in O (the reverse being true for the α phase). Thus, creep tests were performed on model Zr-Nb-O thin sheets with Nb and O concentrations representative of each phase in the considered temperature range. New α and β creep flow equations were developed from this extended experimental database and used to compute, via a finite element model, the creep rates of the two-phase material. The 3D-morphology of phases (β grains nucleated at α grain boundaries) was explicitly introduced in the computations. The effect of phase morphology on the macroscopic creep flow was shown using this specific morphology, compared to other typical morphologies and to experimental data. M5® is a registered trademark of AREVA NP
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Trégo, Gwenaël. "Comportement en fluage à haute température dans le domaine biphasé (α + β) de l'alliage M5®." Phd thesis, École Nationale Supérieure des Mines de Paris, 2011. http://pastel.archives-ouvertes.fr/pastel-00688207.
Abstract:
Le comportement en fluage isotherme de l'alliage M5® a été étudié à haute température dans le domaine biphasé (α+β). Une première approche consiste en l'identification des lois de fluage des phases α et β dans leur domaine monophasé respectif puis en l'extrapolation de ces lois dans le domaine biphasé. Cette approche ne permet malheureusement pas de reproduire le comportement expérimental. Une amélioration de ce modèle est développée dans cette étude en prenant en compte deux effets microstructuraux : (i) la taille de grains : des tailles de grains spécifiques contrôlées ont été obtenues en appliquant des traitements thermo-mécaniques au matériau. Des essais de fluage dans les domaines quasi-α et quasi-β ont ainsi mis en évidence un fort effet de la taille de grains, en particulier dans le régime de fluage diffusionnel. (ii) le contraste micro-chimique entre les phases α et β dans le domaine biphasé : d'après des calculs thermodynamiques et des analyses microstructurales, la phase β est enrichie en Nb et appauvrie en O (inversement pour la phase α). Des essais de fluage ont alors été mis en œuvre sur des alliages Zr-Nb-O dont les teneurs en Nb et O sont représentatives de chaque phase dans le domaine biphasé. Cette base expérimentale a permis de d'identifier de nouvelles lois de fluage pour les phases α et β. Ces lois ont été ensuite implémentées dans un modèle éléments finis afin de simuler le comportement du matériau biphasé. La morphologie 3D des phases (en particulier la germination de la phase β aux joints de grains α) est introduite explicitement dans les simulations afin de mettre en évidence son effet sur le comportement macroscopique. M5® est une marque déposée d'AREVA NP.
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Brake, Derek William. "Effect of β-adrenergic agonists on urea recycling by cattle fed varying levels and forms of nitrogen supplementation." Thesis, Kansas State University, 2009. http://hdl.handle.net/2097/1667.
Abstract:
Master of ScienceDepartment of Animal Sciences and Industry
Evan C. Titgemeyer
Two experiments analyzed effects of zilpaterol-HCl and nitrogen supplementation in the form of either dried distiller’s grains with solubles (DDGS) or urea fed to steers. In Experiment 1, steers were fed corn-based diets: control (CON; 10.2% CP), urea (UREA; 13.3% CP), or DDGS (14.9% CP). Nitrogen intake differed among treatments (99, 151, and 123 g/d for CON, DDGS, and UREA). Urea-N synthesis tended to be greater for DDGS (118 g/d) than for UREA (86 g/d), which tended to be greater than CON (52 g/d). Urinary urea-N excretion was greater ([italics]P[italics]<0.03) for DDGS (35.1 g/d) and UREA (28.6 g/d) than for CON (12.7 g/d). Gut entry of urea-N (GER) was numerically greatest for DDGS (83 g/d), intermediate for UREA (57 g/d), and least for CON (39 g/d). Urea-N returned to the ornithine cycle tended to be greater for DDGS (47 g/d) than for UREA (27 g/d) or CON (16 g/d). The percent of microbial N flow derived from recycled urea-N tended ([italics]P[italics]=0.10) to be greater for DDGS (35%) than for UREA (22%) or CON (17%). The percent of urea production captured by ruminal bacteria was greater ([italics]P[italics]<0.03) for CON (42%) than for DDGS (25%) or UREA (22%). Experiment 2 diets were identical to those used in Experiment 1. In addition, steers were also fed either 0 or 60 mg/d zilpaterol-HCl. Dietary CP was 9.6, 12.4, and 13.7% for CON, UREA, and DDGS, respectively. Zilpaterol increased ([italics]P[italics]<0.01) total DMI and N intake; however, zilpaterol did not affect urea entry rate ([italics]P[italics]=0.80) or GER ([italics]P[italics]=0.94). Urea entry rate and GER were numerically greater for DDGS than CON and UREA. In conclusion, zilpaterol did not influence urea entry rate or GER. This lack of response in the face of greater N intake was interpreted to suggest that zilpaterol may reduce urea production and GER at constant N intake.
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Lavogiez, Cyril. "Étude de l’effet « dwell » dans le Ti-6Al-4V : mécanismes de déformation et d’amorçage de fissures en relation avec l’orientation cristallographique locale de la phase αp Concurrent operation of slip and twinning under cycling loading of Ti-6Al-4V Analysis of deformation mechanisms operating under fatigue and dwell-fatigue loadings in an α/β titanium alloy Deformation processes at crack initiation site under cyclic loading of Ti-6Al-4V with a dwell period On the mechanism of fatigue and dwell-fatigue crack initiation in Ti-6Al-4V Why do titanium alloys withstand more strain under dwell-fatigue than under fatigue loadings." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2020. http://www.theses.fr/2020ESMA0004.
Abstract:
L’introduction d’un temps de maintien à charge maximale au cours d’un chargement mécanique cyclique d’un alliage de titane (α+β), conduit à une réduction du nombre de cycles à rupture. Cet abattement de durée de vie, appelé effet «dwell», s’accompagne également d’une augmentation de la déformation plastique à rupture et d’une transition de l’amorçage des fissures fatales de la surface vers le cœur. Malgré plus de 40 ans de recherche, ce phénomène, qui est lié à la viscoplasticité des alliages de titane à température ambiante, reste mal expliqué. Dans la littérature, les efforts se sont principalement concentrés sur l’étude du mécanisme d’amorçage de fissure. Différents modèles ont été proposés mais le manque de données expérimentales statistiques sur les sites d’amorçage de fissure en dwell-fatigue, ne permet pas de converger vers un accord général. De plus, peu d’études ont porté sur l’influence du temps de maintien sur les processus de déformation, qui précèdent et sont au cœur de l’amorçage des fissures de fatigue dans les alliages de titane. Les travaux de thèse présentés se proposent ainsi d’étudier l’effet «dwell» à travers l’influence du temps de maintien sur les liens entre la plasticité et l’amorçage des fissures. Pour cela, plusieurs essais de fatigue et de dwell-fatigue ont été effectués sur un alliage Ti-6Al-4V avec une microstructure bimodale. Une étude exhaustive de l’ensemble des mécanismes de déformation de la phase αp (glissement basal, prismatique, pyramidal et , aux interfaces et maclage), résultant de champs mécaniques hétérogènes influencés par le report des contraintes entre grains voisins ou l’interaction des bandes de glissement avec un joint de grain, a d’abord été effectuée. Les techniques d’analyse EBSD et d’analyse des lignes de glissement ont été utilisées dans ce but. Les mécanismes de déformation ont été comparés à des taux de déformation plastique similaires pour différentes durées de maintien. Enfin, les configurations microstructurales d’amorçage de fissures ont été caractérisées. Un mécanisme d’amorçage de fissures nouveau a été mis en évidence en lien avec des configurations microstructurales spécifiques, en fatigue comme en dwell-fatigue et en surface comme à coeur. L’association des résultats sur les modes de déformation et l’amorçage des fissures a permis finalement de de suggérer les points où de futurs efforts pourront se concentrerThe introduction of a hold time at maximum stress during the loading of an (α+β) titanium alloys leads to a reduction in the number of cycles to failure. This life debit, called “dwell effect” goes in hand with a higher plastic strain uptake at failure and a transition of the fatal crack initiation from surface to the volume. Despite more than 40 years of scientific research, the origins of this phenomenon, which is closely linked to the viscoplastic behavior of titanium alloy at room temperature, remains unclear. In the literature, the main efforts were focused on elucidating the mechanism of crack initiation. Several models have been proposed but the lack of experimental data with a statistical significance about the crack initiation sites under dwell-fatigue loading prevented to reach a general agreement. Moreover, few studies have investigated the influence of the hold time at maximum stress on the deformation mechanisms, although they precede crack initiation and govern the associated mechanisms under cyclic loading. The presented work is a study of the dwell effect through the analysis of the influence of the hold time at maximum stress in order to clarify the link between plasticity and crack initiation. In this aim, several fatigue and dwell fatigue tests have been performed on a Ti-6Al-4V alloy with a bimodal microstructure. An extensive study of deformation mechanism of the αp phase in relation to the heterogeneous mechanical fields influenced by load shedding between neighboring grains or interactions between slip bands and grain boundaries, has been performed. EBSD analyses and slip trace analysis were employed in this aim. The deformation mechanisms identified by these techniques (basal, prismatic, pyramidal and slip, interface sliding and twinning) were compared for different hold periods at maximum stress at similar cumulated plastic strain. Then, a microstructural configuration promoting crack initiation has been identified. It enabled to propose a new crack initiation mechanism. In addition, this mechanism is unique for crack initiation under fatigue and dwell-fatigue loadings and for surface and subsurface crack initiation. The combination of the results obtained on plasticity and crack initiation clarifies some features of the dwell effect and suggests some outlooks for future work
Books on the topic "Grain β":
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Attems, Johannes, and Kurt A. Jellinger. Neuropathology. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199644957.003.0006.
Abstract:
This chapter describes the main neuropathological features of the most common age associated neurodegenerative diseases including Alzheimer's disease, Parkinson's disease and dementia with Lewy bodies as well as other less frequent ones such as multiple system atrophy, Pick's disease, corticobasal degeneration, progressive supranuclear palsy, argyrophilic grain disease, neurofibrillary tangle dominant dementia, frontotemporal lobar degeneration with TDP-43 pathology and Huntington's disease. Likewise cerebral amyloid angiopathy, hippocampal sclerosis, vascular dementia and prion diseases are described. A main aim of this chapter is to assist the reader in interpreting neuropathological reports, hence criteria for the neuropathological classifications of the major diseases are provided. One section covers general considerations on neurodegeneration and basic pathophysiological mechanisms of tau, amyloid-β, α-synuclein, TDP-43 and prions are briefly described in the sections on the respective diseases. Finally, one section is dedicated to cerebral multimorbidity and we give a view on currently emerging neuropathological methods.
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Gallego-Villada, Luis A. Efecto de las características de las materias primas nacionales en la eficiencia de la producción de nopol. Universidad Internacional de Andalucía, 2022. http://dx.doi.org/10.56451/10334/6256.
Abstract:
XIII Premio de Estudios Iberoamericanos La Rábida 2020 del Grupo de Universidades Iberoamericanas La Rábida en la categoría de mejor trabajo fin de máster oficial de temática perteneciente a las áreas Científico-Técnicas. Este trabajo ha sido presentado y está depositado en el Repositorio Institucional de la Universidad de Antioquia (http://hdl.handle.net/10495/15038). Esta obra muestra el gran potencial que tienen las materias primas colombianas para la síntesis de productos de la química fina tal como el nopol, utilizando catalizadores heterogéneos. El nopol tiene aplicaciones relevantes en la industria de aromas y fragancias, pero también puede ser utilizado como intermediario en la síntesis de productos empleados en la producción de pesticidas y productos del hogar. Por otra parte, se muestra una caracterización detallada del material Sn/MCM-41, a partir de la estructura cristalina, la morfología, las propiedades texturales, la fuerza y tipo de sitios ácidos, y el tipo de especies activas. Este catalizador se sintetiza utilizando silicato de sodio producido en Colombia, como fuente de silicio, lo cual es significativamente más económico que la fuente de silicio tradicional, tetraetil ortosilicato. Finalmente, se realizó un estudio detallado con aceite de trementina como fuente de β-pineno y paraformaldehído comercializado localmente, mediante un Diseño Central Compuesto, determinando condiciones óptimas para la producción de nopol.
Book chapters on the topic "Grain β":
1
Ukyo, Yoshio, and Shigetaka Wada. "α‘ /β’ Sialon Composites." In Grain Boundary Controlled Properties of Fine Ceramics, 112–24. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-1878-1_13.
2
Pilchak, Adam L., Dipankar Banerjee, and J. C. Williams. "Grain Boundary α and β Grain Boundary Orientation in Titanium Alloys." In Proceedings of the 13th World Conference on Titanium, 425–30. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119296126.ch66.
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Salib, Matthieu, Mien Teixeira, Lionel Germain, Benoit Denand, Nathalie Gey, and Elisabeth Aeby-Gaurier. "Influence of α Precipitation at β/β Grain Boundaries on a Microtexture in A β- Metastable Titanium Alloy with and without Previous Deformation." In Proceedings of the 13th World Conference on Titanium, 405–14. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119296126.ch63.
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Saito, Noritaka, Daiji Nakata, Kunihiko Nakashima, and Ayumu Umemoto. "Grain Growth of β-Silicon Nitride in Re-Mg-Si-O-N Liquid." In Ceramic Transactions Series, 71–80. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9781118144091.ch8.
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Saito, Noritaka, Daiji Nakata, Ayumu Umemoto, and Kunihiko Nakashima. "Grain Growth of β-Silicon Nitride in RE-Mg-Si-O-N Liquid." In Key Engineering Materials, 265–70. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-965-2.265.
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Ceja-Cárdenas, Leonel, José Lemus-Ruiz, Sebastián Diaz de la Torre, and Egberto Bedolla-Becerril. "Grain Growth of β-Si3 N4 using Y2 O3 and Al2 O3 as Sintering Aids." In Ceramic Transactions Series, 71–77. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118486955.ch7.
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Donoghue, Jack, Jagjit Sidhu, Andrew Wescott, and Phillip Prangnell. "Integration of Deformation Processing with Additive Manufacture of Ti-6A1-4V Components for Improved β Grain Structure and Texture." In TMS2015 Supplemental Proceedings, 437–44. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781119093466.ch55.
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Donoghue, Jack, Jagjit Sidhu, Andrew Wescott, and Phillip Prangnell. "Integration of Deformation Processing with Additive Manufacture of Ti-6Al-4V Components for Improved β Grain Structure and Texture." In TMS 2015 144th Annual Meeting & Exhibition, 437–44. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-48127-2_55.
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Matsumoto, J., Hiroshi Anada, and Mitsuaki Furui. "The Effect of Grain Size and Amount of β Phase on the Properties of Back-Torsion Working in 60/40 Brass." In THERMEC 2006 Supplement, 661–66. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-429-4.661.
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Poorganji, Behrang, S. Hotta, Taichi Murakami, Takayuki Narushima, Yasutaka Iguchi, and Chiaki Ouchi. "The Effect of Small Amounts of Yttrium Addition on Static and under Superplastic Deformation Grain Growth in Newly Developed α+β Type, Ti-4.5Al-6Nb-2Mo-2Fe Alloy." In THERMEC 2006 Supplement, 970–75. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-429-4.970.
Conference papers on the topic "Grain β":
1
Deshpande, Abhishek, Qian Jiang, and Abhijit Dasgupta. "Anisotropic Plastic Constitutive Properties of SAC305 Single Crystal Solder Joints." In ASME 2022 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/ipack2022-94505.
Abstract:
Abstract Micro-scale Sn-Ag-Cu (SAC) solder interconnects have oligocrystalline grain structure with one to few grains in each solder joint. As well documented in the literature, SAC solder joint consisting of 96.5% β-Sn is highly anisotropic due to the inherently anisotropic mechanical behavior of β-Sn. Therefore, each joint exhibits a unique mechanical response. However, due to the complexities in the quantification of microstructure and finite element (FE) modeling methodology, engineers typically model solder joints as homogenous isotropic structures with directionally averaged mechanical properties. These approximations cause inaccurate prediction of strain levels in the solder and in turn leads to uncertainties in lifetime predictions. A key challenge in grain-scale anisotropic modeling of solder joints, is the lack of widely accepted anisotropic inelastic mechanical properties of solder grains in the literature. The goal of this paper is to determine rate-independent plastic constitutive behavior of Anisotropic SAC305 single grains. Monotonic tensile and shear tests are conducted at room temperature on a set of single-grain SAC305 solder joints. The grain structure for each test specimen is characterized with EBSD and finite element modeling is used to iteratively extract model constants for Hill-Holloman continuum plasticity model, which utilizes Hill’s anisotropic yield criterion along with a Holloman Power-Law plasticity model to represent each grain. Plastic deformation in the grain boundaries is ignored.
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Yamagata, Ryosuke, Yotaro Okada, Hirotoyo Nakashima, and Masao Takeyama. "Microstructure Effect on Enhancement of Room-Temperature Ductility in β-Ti Containing γ-TiAl Based Alloys." In AM-EPRI 2019, edited by J. Shingledecker and M. Takeyama. ASM International, 2019. http://dx.doi.org/10.31399/asm.cp.am-epri-2019p1446.
Abstract:
Abstract Effects of microstructure constituents of α2-Ti3Al/γ-TiAl lamellae, β-Ti grains and γ grains, with various volume fractions on room-temperature ductility of γ-TiAl based alloys have been studied. The ductility of the alloys containing β phase of about 20% in volume increases to more than 1% as the volume fraction of γ phase increases to 80%. However, γ single phase alloys show very limited ductility of less than 0.2%. Microstructure analysis have revealed that intragranular fracture along γ/γ grain boundary occurred in γ single phase alloy whereas it does not along β/γ interphase in alloys containing β phase. In addition, local strain accumulations along β/γ interphase have been confirmed. The present results, thus, confirmed the significant contribution of β phase, especially the existence of β/γ interphase to enhancement of the room-temperature ductility in multicomponent TiAl alloys.
3
Ivasishin, Orest, Pavlo Markovsky, Marta Pozuelo, and Sergey V. Prikhodko. "Effect of Severe Hot Forging and Rolling on Microstructure, Texture and Tensile Properties of Titanium Metastable Beta-Alloys." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63767.
Abstract:
The influence of specific method of severe hot deformation, forging plus rolling, that ensures true deformation |ε| = 1.39 in single pass was studied on two metastable β-class titanium alloys VT22 (Ti-5.0Al-4.79Mo-4.70V-0.97Fe-0.71Cr) and TIMETAL-LCB (Ti-1.50Al-6.82Mo-4.47Fe), wt%. The results on microstructure, crystallographic texture and tensile properties are presented. It was found that this type of severe deformation forms elongated not-recrystallized β-microstructure with sharp axial (110)β texture, and fine α-precipitates inside the β-grains. In as-deformed condition both alloys are characterized by high tensile strength (above 1500 MPa) and very low ductility. Additional annealing at α + β temperatures does not change β-grain microstructure and crystallographic texture, but gives the structure a balance of strength and ductility. It looks very attractive for practical application of the alloys. Results are discussed in terms of specific mechanism of deformation accommodation.
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Shen, Xinwei, and Shuting Lei. "Cutting Simulation of Laser Assisted Milling of Silicon Nitride Ceramics Using PFC2D." In ASME 2009 International Manufacturing Science and Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/msec2009-84041.
Abstract:
Since laser assisted milling (LAMill) exhibits complicated characteristics in ceramic machining, this paper applies a distinct-element code, PFC2D (Particle Flow Code in Two-Dimensions), to conduct cutting simulation of laser assisted slab milling and explore its machining mechanism. The microstructure of a β-type silicon nitride ceramic (β-Si3N4) is modeled at grain scale. Clusters are used to simulate the rod-like grains of β-Si3N4. Parallel bonds are employed to represent the connection between intergranular glass phase and grains. A temperature-dependent PFC specimen is created for simulation of LAMill. A special milling cutter is designed for improving the computing efficiency. Simulation results show that the cutting force is strongly related to crack formation and propagation. The specific cutting energy decreases as the cutting temperature increases.
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Shihua Yang, Chunqing Wang, Yanhong Tian, Pengrong Lin, and Le Liang. "Limited β-Sn grain number of miniaturized Sn-Ag-Cu solder joints." In 2008 International Conference on Electronic Packaging Technology & High Density Packaging (ICEPT-HDP). IEEE, 2008. http://dx.doi.org/10.1109/icept.2008.4607056.
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González Jiménez, K. G. "Superplasticity of Ti-6Al-7Nb alloys with different initial microstructures processed by high-pressure torsion." In Superplasticity in Advanced Materials. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902615-7.
Abstract:
Abstract. Ti-6Al-7Nb alloy was quenched below and above the β-phase field and processed by high-pressure torsion (HPT) to produce different grain sizes in the ultra-fine range. The influence of temperature and strain rate over the superplastic properties, activation energy and strain rate sensitivity were evaluated by high temperature tensile tests. The mechanical properties were complemented with Vickers microhardness measurement of heat treated and HPT-processed samples. The crystallographic analysis was performed through XRD and EBSD studies in the grip and tip of the high temperature tensile specimens. Microhardness measurements show significant hardening with respect to the imposed strain after HPT. Meanwhile, high superplastic elongation of 1200% was accomplished at 850 °C with a strain rate of 2x10-3 s-1. EBSD studies of the failed specimens suggest that the tip part exhibited dynamic recrystallization during tensile test, which produced a larger grain size of ~5.1 µm and higher fraction of β phase of 3.7%, with respect to the grip part under static recrystallization, which attained ~3.4 µm grain size and 3.3% β phase fraction.
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Huang, Mingliang L., Jiameng M. Kuang, and Hongyu Y. Sun. "Electromigration-Induced β-Sn Grain Rotation in Lead-Free Flip Chip Solder Bumps." In 2019 IEEE 69th Electronic Components and Technology Conference (ECTC). IEEE, 2019. http://dx.doi.org/10.1109/ectc.2019.00312.
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Karaman, Ibrahim, and G. Guven Yapici. "Effect of Severe Plastic Deformation on the Mechanical Behavior of Ti-6Al-4V." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-43712.
Abstract:
The present work focuses on the microstructural evolution and resulting room temperature mechanical properties of P/M Ti-6Al-4V severely deformed at different temperatures (550°C to 800°C) using Equal Channel Angular Extrusion (ECAE). The bulk materials are extruded through two channels of equal cross section intersecting an angle of 90 degree. Microstructure and mechanical properties of extruded billets are reported through electron microsopy observations and tension, compression and hardness experiments. Results are compared for different extrusion conditions including variations in temperature and processing route. Higher hardness values are obtained after ECAE compared to as-received values. These improvements are correlated with the grain refinement, phase refinement and texture produced during ECAE. The most favorable microstructure in terms of refined grains was two passes at 600°C. The ultimate goal is to develop ECAE thermomechanical-processing maps for the selection of processing schedules to obtain desired end microstructures and improved fatigue life in Ti-Al-V based materials. The investigations revealed that: 1. ECAE shear deformation leads to refinement in β plates and elimination of piror β boundaries. Decreasing extrusion temperature and increasing number of passes decreases α plate size and grain size. Refined α grain size leads to a significant increase in tensile and compressive flow stresses at room temperature. 2. The second extrusion pass at 800°C increased both the yield strength and ductility. This was attributed to the observed α plate refinement. 3. Cavitation at the interface between β strips and α plates at 550°C was thought to be the reason for low ductility and relatively low strain hardening at room temperature. 4. Texture has a pronounced effect on mechanical properties. Tension/compression asymmetry in flow strengths and strain hardening coefficients may be described by the activation of differing slip systems under tension and compression loading because of texture.
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Mondal, Debabrata, Jeffrey C. Suhling, Elham Mirkoohi, and Pradeep Lall. "Effects of Grain to Sample Volume Ratio on the Deformation Behavior of Polycrystal SAC Samples Subjected to Shear Loads." In ASME 2023 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/ipack2023-112034.
Abstract:
Abstract The study of size effects in electronic structural components and solders is important when dimensions are being continually downsized. It is crucial to obtain a constitutive model that describes material behavior of electronic package solders at small scales. Ample studies are available to describe the deformation behavior of SAC alloys at bulk level. For instance, stress-strain, creep, and shear behaviors have been investigated for bulk SAC samples. Although solder joints are very small in dimensions, most researchers have not explained the solder deformation considering size effects. With further miniaturization of solder joints in high density packaging, the localized material behavior can influence significantly the overall system. For instance, knowledge of individual grain properties of a crystalline materials is essential in determining material behavior of miniaturized products. Sn-Ag-Cu (SAC) alloys are the most widely used lead-free materials to fabricate solder interconnects in microelectronic packaging. For most of the SAC alloys, more than 95% weight percentage is β-Sn which is a highly anisotropic material in terms of elastic modulus (E) and coefficient of thermal expansion (CTE). Moreover, due to the crystalline nature of β-Sn material, plastic deformation beyond the elastic limit is described by various atomic planes and directions, which are termed as slip systems. Ten different slip families with 32 slip systems have been recognized for β-Sn body-centered tetragonal (BCT) crystals. When external loads are applied on solder joints, plastic deformation is dictated by the movement of dislocations and direction of deformation is defined by slip systems. When structural components are miniature in dimensions, crystal plasticity theory can accurately predict the material response considering crystallographic deformation mechanisms. In this study, a crystal plasticity-based DAMASK code was used to explain the mesoscale deformation behavior of polycrystal beta-tin samples. Polycrystalline beta-tin samples were obtained using Voronoi tessellation in NEPER with random grain orientations, which is the case for real samples. Shear simulations were performed for a sample with reasonably large number of grains. The model was then calibrated with experimental stress-strain data for a reflowed SAC305 alloy to determine a set of beta-tin slip properties. Subsequently, multiple polycrystalline models were generated with varying number of Sn grains, and a spectral solver was used to determine the sample responses under shear loads on three orthogonal planes. Samples with large number of grains exhibited isotropic deformation behavior. However, samples with fewer number of grains demonstrated anisotropic behavior. This study determined the overall average grain size to sample size ratio at which isotropic behavior breaks down under the application of shear loads.
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Huang, C., Y. Xie, C. Verdy, M. Planche, H. Liao, G. Montavon, W. Li, and Y. Feng. "Microstructural Evolution and Mechanical Property Enhancement of a Cold Sprayed Cu-Zn Alloy Coating by Post-Spray Friction Stir Processing." In ITSC2017, edited by A. Agarwal, G. Bolelli, A. Concustell, Y. C. Lau, A. McDonald, F. L. Toma, E. Turunen, and C. A. Widener. DVS Media GmbH, 2017. http://dx.doi.org/10.31399/asm.cp.itsc2017p0425.
Abstract:
Abstract An innovative hybrid process which combines the two very effective solid-state techniques of cold spraying (CS) and friction stir processing (FSP), was proposed to fabricate a high-strength ultrafine-grained Cu-Zn coating. Results show that the CS coating had an elongated microstructure with 78.42% of low-angle grain boundaries. Following FSP, there appear ultrafine grains with 90.47% of high-angle grain boundaries and a composition of α, β' and γ phases while the CS coatings was mainly α. Significant mechanical properties enhancement is achieved, i.e. with the ultimate tensile strength increasing from 87.2 MPa to 257.5 MPa and fracture elongation increasing from 0.17% to 0.81%. The precipitates have a significant effect on the fracture behavior of FSP coatings.