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1
Li, Zhuang, Zhen Zheng, Da Tong Qiu, Li Zhe Guo, Xin Gao, Tao Yu e Zhao Hua Li. "Effect of Overaging Temperature on the Mechanical Properties of Ultra-High Strength Multiphase Steel". Applied Mechanics and Materials 556-562 (maggio 2014): 249–52. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.249.
Testo completoAbstract (sommario):
Overaging after intercritical annealing of ultra-high strength multiphase steel was conducted in a continuous annealing simulator of the laboratory. The effect of overaging temperature on the mechanical properties of multiphase steel has been studied by observing the microstructural evolution during overaging. The results have shown that multiphase microstructures containing ferrite, martensite, bainite and retained austenite were obtained by overaging treatments after intercritical annealing in ultra-high strength steel, and overaging temperatures affected all constituents of the microstructure. UTS and YS dereased with increasing overaging temperature, and TEL decreased after overaging at 350°C. A good combination of ultimate tensile strength (1400MPa), yield strength (795MPa), and total elongation (15%) was exhibited for the specimen overaged at 250°C. This was attributed to synthetic action of all constituents of ultra-high strength steel microstructure.
2
Arruabarrena, Jon, e Jose M. Rodriguez-Ibabe. "Enhancement of the AISI 5140 Cold Heading Wire Steel Spheroidization by Adequate Control of the Initial As-Rolled Microstructure". Metals 11, n. 2 (27 gennaio 2021): 219. http://dx.doi.org/10.3390/met11020219.
Testo completoAbstract (sommario):
The effect of the initial microstructure and soft annealing temperature on cementite spheroidization and microstructure softening is studied on an AISI 5140 hot-rolled wire. In coarse pearlite microstructure (λ: 0.27 μm), the cementite spheroidization progresses slowly under subcritical treatment, and the microstructure does not achieve the minimum G2/L2 IFI rating defined in the ASTM F2282 to be used in cold forming operations under any of the annealing treatment studies. Fine pearlite (λ: 0.10 μm) and upper bainite microstructures are more prone to spheroidization, and the minimum G2/L2 IFI rating is achieved under subcritical annealing at 720 °C for 6 h. Independent of the initial microstructure, even in the case of martensite, low hardness values within 165–195 HV are attained after imposing a 10 h long treatment at 720 °C. Annealing treatments conducted at 660 °C and 600 °C on pearlitic microstructures give rise to very poor softening. The G2/L2 rating is not achieved in any of the treatments applied at these two temperatures in this study. In pearlitic microstructures, the spheroidization progresses according to a fault migration mechanism, enhanced by the presence of defects such as lamella terminations, holes, and kinks. In the upper bainite, the row-like disposition of the cementite along the ferrite lath interface provides necks where dissolution and consequent lamellae break-up take place quickly under annealing.
3
Scheriau, Stephan, Thomas Schöberl, Siegfried Kleber e Reinhard Pippan. "Recrystallization and Grain Growth Behavior of SPD Deformed 316L Stainless Steel". Advanced Materials Research 89-91 (gennaio 2010): 491–96. http://dx.doi.org/10.4028/www.scientific.net/amr.89-91.491.
Testo completoAbstract (sommario):
The microstructural evolution, the changes in microhardness and the recrystallization behavior of a modified 316L stainless steel were investigated during high pressure torsion (HPT) and subsequent annealing. To study the impact of the governing process parameters on the evolving microstructures, the applied strain, the strain path and the annealing temperatures were varied. In contrast to ordinary single phase steels, which showed a decrease in the structural size ending in a saturation of the microstructural refinement between an equivalent strain eq of 10 and 15, HPT of the modified 316L results in a steep increase in shear stress at very small strains and the saturation region is reached far before eq = 10. Studies using the transmission electron microscope (TEM) revealed that at large strains the original coarse grains are converted by the massive intersection and fragmentation of twins into a nanometer-scaled microstructure. In the case of monotonic HPT, shock annealing of the deformed discs results in rows of fine and coarse grains. In the cyclic deformed discs a homogenous, fine-grained and almost fully recrystallized microstructure was observed. The results clearly show that both the strength and ductility of the material can be significantly influenced by SPD and subsequent annealing. Possible reasons for the observed differences in the deformation and annealing behavior are discussed.
4
Sun, Yangyang, Hui Chang, Zhigang Fang, Yuecheng Dong, Zhenhua Dan, Yanhua Guo e Lian Zhou. "Study on Microstructure and Mechanical Properties of Low Cost Ti-Fe-B Alloy". MATEC Web of Conferences 321 (2020): 11029. http://dx.doi.org/10.1051/matecconf/202032111029.
Testo completoAbstract (sommario):
Microstructure evolution and mechanical properties of low cost Ti-2Fe-0.1B alloy under different heat treatment were studied. Results indicated that two kinds of equiaxed microstructures with different characteristics were obtained in conventional and double annealing, and typical lamellar microstructure was obtained in β annealing. Tensile test results shown that as-received rolled alloy possess highest strength and plasticity simultaneously due to fine and entangled microstructure. Uniform equiaxed dimples were observed in microstructure, which revealed ductile fracture morphology. Key words: titanium alloy; microstructure; heat treatment; mechanical properties
5
Terada, Daisuke, Bo Long Li, Masaaki Sugiyama e Nobuhiro Tsuji. "Low Temperature Recrystallization of High Purity Iron Severely Deformed by ARB Process". Materials Science Forum 558-559 (ottobre 2007): 357–62. http://dx.doi.org/10.4028/www.scientific.net/msf.558-559.357.
Testo completoAbstract (sommario):
Recrystallization behavior of SPD processed high purity iron was studied. The 99.95% iron sheet was deformed by the accumulative roll-bonding (ARB) process up to 8 cycles (equivalent strain of 6.4) at ambient temperature. Subsequently, the ARB-processed specimens were annealed for 1.8ks at various temperatures from 300°C to 500°C. The microstructures of these specimens were characterized by TEM and SEM/EBSP. The microstructure of the as-ARB-processed specimens showed the lamellar boundary structure elongated along RD, which was the typical microstructure of the ARB-processed materials. The mean interval of the lamellar boundaries was about 100 nm. After annealing at 400°C, the ARB specimen showed a partially recrystallized microstructure composed of equiaxed grains with grain size larger than 10 5m and the recovered lamellar boundary structure. After annealing above 500°C, the microstructures were filled with equiaxed recrystallized grains. These results suggest that conventional discontinuous recrystallization characterized by nucleation and growth occurs during annealing at annealing temperature above 400 °C. In previous work reported about the annealing behavior of the low carbon IF steel ARB processed, the continuous recrystallization occurred during annealing at annealing temperature above 600 °C. The recrystallization temperature of the pure iron was much lower than the IF steel and the recrystallization process were significantly different. This difference was suggested to be caused by inhomogeneous microstructure in the pure iron ARB-processed.
6
Nasiri, Z., e H. Mirzadeh. "Spheroidization heat treatment and intercritical annealing of low carbon steel". Journal of Mining and Metallurgy, Section B: Metallurgy 55, n. 3 (2019): 405–11. http://dx.doi.org/10.2298/jmmb180813033n.
Testo completoAbstract (sommario):
Spheroidization annealing of low carbon steel and its effects on the microstructure and mechanical properties of dual phase (DP) steel were studied. It was revealed that the reduction in strength and hardness of the quenched martensitic microstructure was much more pronounced compared to the fully annealed ferritic-pearlitic banded microstructure with spheroidizing time. This was related to the confinement of spheroidized carbide particles to distinct bands in the latter, and the uniform dispersion of carbides and high-temperature tempering of martensite in the former. During intercritical annealing of the spheroidized microstructures, the tendency to obtain martensite particles as discrete islands was observed. This, in turn, resulted in an inferior strength-ductility balance compared to the DP steel obtained from the intercritical annealing of martensite, which negated the usefulness of the spheroidized microstructures as the initial microstructures for the processing of DP steels.
7
Wu, Gui Lin. "Recrystallization Microstructure and Texture of Highly Strained Commercial Purity Aluminium Alloy". Materials Science Forum 783-786 (maggio 2014): 282–87. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.282.
Testo completoAbstract (sommario):
The microstructural and textural evolutions during annealing of a highly strained (ε=4.0) commercial purity aluminium (AA1200) were followed by electron backscatter diffraction (EBSD). Boundary spacings were analyzed for crystallites of different crystallographic orientations. It was found that initially during the annealing the microstructural evolution is dominated by recovery of the highly strained microstructure, while later the microstructure consists of identifiable grains nucleating and growing at the expense of deformed and recovered matrix. No much texture change occursduring early stages of annealing, whereas a cube texture evolves and dominates after complete recrystallization.
8
Liu, Mu Lin, Naoki Takata, Asuka Suzuki e Makoto Kobashi. "Inhomogeneous Microstructure and its Thermal Stability of AlSi10Mg Lattice Structure Manufactured via Laser Powder Bed Fusion". Materials Science Forum 1016 (gennaio 2021): 826–31. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.826.
Testo completoAbstract (sommario):
The inhomogeneous microstructure and its change by annealing for an AlSi10Mg lattice structure with a body-centered cubic unit cell additively manufactured via laser powder bed fusion (LPBF) were investigated. The as-built lattice structure exhibited a cellular microstructure consisting of a number of primary α-Al phases decorated with α-Al/Si eutectic structure. The developed microstructure varied depending on the locations of the node and strut parts of the lattice structure. At the location near the bottom surface of the node part, the cellular microstructure became coarser and more equiaxed than those at the location near the top surface. At the location near the bottom surface of the strut part, the columnar α-Al phases were often elongated along the direction of the strut part. After the annealing at 300 °C for 2 h, numerous Si particles finely precipitated within the primary α-Al phases and coarsening of the eutectic Si phases occurred. After the annealing at 530 °C for 6 h, the microstructural characteristics changed significantly. A significant coarsening of the Si particles and the formation of Fe-containing intermetallic phase (β-AlFeSi) with a plate-shaped morphology occurred. The microstructures became homogeneous in the whole area of the lattice structure annealed at 530 °C for 6 h.
9
Yan, Bin, Hongbo Li, Jie Zhang e Ning Kong. "The Effect of Initial Annealing Microstructures on the Forming Characteristics of Ti–4Al–2V Titanium Alloy". Metals 9, n. 5 (17 maggio 2019): 576. http://dx.doi.org/10.3390/met9050576.
Testo completoAbstract (sommario):
In this study, the effect of initial annealing microstructure of Ti–4Al–2V (TA17) alloy on forming characteristic was studied, so as to provide a basis for quality control of plastic forming of titanium alloy parts. The titanium alloy always undergoes annealing treatment before forming, due to different microstructures present different mechanical properties. The TA17 with different microstructures are obtained by means of various annealing treatment temperatures. The tensile behavior of TA17 is investigated at room temperature and 900 °C under constant strain rate of 0.01 s−1. The experimental results show that the mechanical properties of TA17 are sensitive to the initial microstructure before deformation. The microstructure of TA17 at 850 °C (2 h) is the equiaxed primary α-phase after the annealing process. It exhibits good plasticity at room temperature. This phenomenon is also confirmed from fracture morphology from the scanning electron microscope (SEM) analysis. At 900 °C, which is a high tensile temperature, the alloy with equiaxed primary α-phase performs outstanding plasticity compared with other microstructures. This work establishes a good understanding on the relationship between the mechanical properties and microstructures of TA17 at a wide temperature range.
10
Steineder, Katharina, Daniel Krizan, Reinhold Schneider, Coline Beal e Christof Sommitsch. "The Effects of Intercritical Annealing Temperature and Initial Microstructure on the Stability of Retained Austenite in a 0.1C-6Mn Steel". Materials Science Forum 879 (novembre 2016): 1847–52. http://dx.doi.org/10.4028/www.scientific.net/msf.879.1847.
Testo completoAbstract (sommario):
The effects of the intercritical annealing temperature and initial microstructure on the stability of retained austenite were investigated for a 0.1C-6Mn (wt-%) steel. Medium-Mn transformation-induced plasticity (TRIP) steels exhibit a strong dependence of their mechanical properties on the variation of intercritical annealing temperature. This behavior is strongly linked to the amount and stability of the retained austenite. Thus, interrupted tensile tests were used to examine the effect of annealing temperature on the stabilization of the retained austenite. Detailed microstructural investigations were employed to elaborate the effects of its chemical and mechanical stabilization. Furthermore, the final microstructure was varied by applying the batch annealing step to an initial non-deformed and deformed microstructure respectively. Retained austenite stability along with resulting mechanical properties of the investigated medium-Mn TRIP steel was significantly influenced as the amount and morphology of the respective phases altered as a consequence of both initial microstructure and applied intercritical annealing temperature.
11
Zhao, Yan Chun, Wen Long Ma, Xiao Peng Yuan, Zhi Ping Zhao, Ming Yuan Huang, Sheng Zhong Kou e Chun Yan Li. "Influence of Annealing Treatment on Microstructure and Mechanical Properties of Fe-Cu-Si-Al Amorphous Composites". Materials Science Forum 849 (marzo 2016): 71–75. http://dx.doi.org/10.4028/www.scientific.net/msf.849.71.
Testo completoAbstract (sommario):
In this study, the bulk amorphous alloys with 3mm in diameter were prepared at different voltages adopting copper mould suction casting method by adding microelement Al to Fe-Cu-Si based amorphous alloy respectively. The microstructures, glass-forming ability, mechanical compressive properties of (Fe0.34Cu0.47Si0.19)95Al5 amorphous composites annealed in different temperature were investigated. The results showed that re-melting of master alloy refined the solidified microstructure and homogenize the composition and microstructure. Moreover, the microstructure was stable with the increase of re-melting times. After relaxation and annealing at low temperature the majority of residual thermal stress was released during annealing at low temperature, with the enlargement of short-range order of amorphous microstructure and the decrease of the most adjacent inter-atomic distance. After proper annealing treatment the hardness and thermal stability of alloy were improved, indicating that the annealing treatment could improve the properties of amorphous alloy.
12
Khorasani, AmirMahyar, Ian Gibson, Moshe Goldberg e Guy Littlefair. "On the role of different annealing heat treatments on mechanical properties and microstructure of selective laser melted and conventional wrought Ti-6Al-4V". Rapid Prototyping Journal 23, n. 2 (20 marzo 2017): 295–304. http://dx.doi.org/10.1108/rpj-02-2016-0022.
Testo completoAbstract (sommario):
Purpose The purpose of this study was to conduct various heat treatments (HT) such as stress relief annealing, mill annealing, recrystallization (α + β) annealing and β annealing followed by furnace cooling (FC) that were implemented to determine the effect of these on mechanical properties and the microstructure of selective laser melted and wrought samples. The mentioned annealings have been carried out to achieve the related standards in the fabrication of surgery implants. Design/methodology/approach In this paper, based on F2924-14 ASTM standard SLM and conventionally wrought parts were prepared. Then HT was performed and different characteristics such as microstructure, mechanical properties, macro-hardness and fracture surface for selective laser melted and wrought parts were analysed. Findings The results show that the high cooling rate in selective laser melting (SLM) generates finer grains. Therefore, tensile strength and hardness increase along with a reduction in ductility was noticed. Recrystallization annealing appears to give the best combination of ductility, strength and hardness for selective laser melted parts, whilst for equivalent wrought samples, increasing HT temperature results in reduction of mechanical properties. Originality/value The contributions of this paper are discussing the effect of different annealing on mechanical properties and microstructural evolution based on new ASTM standards for selective laser melted samples and comparing them with wrought parts.
13
Fan, Y., W. Tian, Y. Guo, Z. Sun e J. Xu. "Relationships among the Microstructure, Mechanical Properties, and Fatigue Behavior in Thin Ti6Al4V". Advances in Materials Science and Engineering 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/7278267.
Testo completoAbstract (sommario):
The microstructures of Ti6Al4V are complex and strongly affect its mechanical properties and fatigue behavior. This paper investigates the role of microstructure on mechanical and fatigue properties of thin-section Ti6Al4V sheets, with the aim of reviewing the effects of microstructure on fatigue properties where suboptimal microstructures might result following heat treatment of assemblies that may not be suited to further annealing, for example, following laser welding. Samples of Ti6Al4V sheet were subjected to a range of heat treatments, including annealing and water quenching from temperatures ranging from 650°C to 1050°C. Micrographs of these samples were inspected for microstructure, and hardness, 0.2% proof stress, elongation, and fracture strength were measured and attributed back to microstructure. Fractography was used to support the findings from microstructure and mechanical analyses. The strength ranking from high to low for the microstructures of thin Ti6Al4V sheets observed in this study is as follows: acicularα′martensite, Widmanstätten, bimodal, and equiaxed microstructure. The fatigue strength ranking from high to low is as follows: equiaxed, bimodal, Widmanstätten, and acicularα′martensite microstructure.
14
Vayrette, Renaud, Christian Rivero, Sylvain Blayac e Karim Inal. "Thickness Effect on Microstructure and Residual Stress of Annealed Copper Thin Films". Materials Science Forum 681 (marzo 2011): 139–44. http://dx.doi.org/10.4028/www.scientific.net/msf.681.139.
Testo completoAbstract (sommario):
In this work, coupled effects of thickness and annealing temperature on both microstructure and residual stress of electroplated copper thin films are studied. Microstructure is investigated by Electron Backscattered Diffraction (EBSD) and residual stress is estimated from samples curvature. All films exhibit highly twinned grains. Except for several microns films, median crystallite size grows with both film thickness and annealing temperature. Concerning residual stress, it decreases, first as the increase of film thickness, and secondly as the decrease of annealing temperature. The comparison between experiments and stress models demonstrates that the root mechanisms of residual stress generation change with annealing temperature. As well as annealing temperature, film thickness determines the level of residual stress through control of microstructure. Furthermore, EBSD investigations confirmed that the relevant microstructural length to define mechanical properties of thin copper films is the median crystallite size.
15
Lee, Jong Chul, Ui Gu Kang, Chang Suk Oh, Sung Joon Kim e Won Jong Nam. "Effects of Deformation Strains and Annealing Temperatures on Mechanical Properties of Martensitic Steels". Materials Science Forum 654-656 (giugno 2010): 218–21. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.218.
Testo completoAbstract (sommario):
The effects of deformation strains and annealing temperatures on microstructures and mechanical properties of martensitic steels were examined. The amount of cold deformation was changed as 30%, 50% and 60%, and annealing temperatures varied from 500°C to 600°C. In samples cold rolled 30%, the dominant microstructure for an annealing at 500°C was dislocation substructures with uniformly distributed rod-shaped carbide particles. For an annealing at 600°C, the microstructure consisted of equiaxed ultrafine grains, spherical carbide particles and elongated dislocation substructures. A proper annealing temperature for martensitic steels received 30% reduction, showing a good combination of a high strength, 1230MPa, and an adequate total elongation. 9.4%, was found as 500°C.
16
El-Bediwi, Abu Bakr, Eman Kashita e Salah M. M. Salman. "Influence of Annealing on Creep Indentation, Surface Properties and Electrochemical Corrosion Behavior of Ni-Cr Based Dental Alloy". International Journal of Applied Sciences and Biotechnology 5, n. 3 (27 settembre 2017): 366–74. http://dx.doi.org/10.3126/ijasbt.v5i3.18295.
Testo completoAbstract (sommario):
Heat treatment is a process in which alloy is heated to get different microstructures and desired properties associated with it which may affect the corrosion rate, nature form and size. Effect of annealing on microstructure, creep indentation, hardness and electrochemical corrosion behavior of Ni63Cr24.6Mo10.8Si1.5Mn0.06C0.04 alloy were investigated. Microstructure of Ni63Cr24.6Mo10.8Si1.5Mn0.06C0.04 alloy changed after annealing at different temperature for two hours. Crystal size of nickel in matrix alloy increased after annealing for two hours at different temperature. Stress exponent, n, Vickers hardness and calculated maximum shear stress of Ni63Cr24.6Mo10.8Si1.5Mn0.06C0.04 alloy decreased after annealing. Corrosion rate of Ni63Cr24.6Mo10.8Si1.5Mn0.06C0.04 alloy increased after annealing for two hours at different temperature. Int. J. Appl. Sci. Biotechnol. Vol 5(3): 366-374
17
Li, Wei, Chen Liang e Xudong Zhang. "Numerical simulation of microstructure evolution of high-purity tantalum during rolling and annealing". Modelling and Simulation in Materials Science and Engineering 30, n. 3 (8 febbraio 2022): 035006. http://dx.doi.org/10.1088/1361-651x/ac4d78.
Testo completoAbstract (sommario):
Abstract In this study, a unified model of thermoplastic deformation and the corresponding microstructure evolution for tantalum with high purity was first proposed by introducing the state variable equations of recrystallization fraction, average grain size, and grain growth. The subroutine of microstructure evolution model was programmed for embedding into the finite element simulation of tantalum plates upon rolling and annealing, and the parameters of microstructure evolution were obtained by fitting the experimental data. Our simulation results reveal the correlations among the microstructures, rolling reduction, annealing temperature and time. Based on these findings, a guideline for optimizing the microstructure of tantalum is proposed.
18
Kane, Genevieve A., M. David Frey e Robert Hull. "Influence of Controlled Cooling Rates During Thermal Processing of Ti 6% Al 4% V Alloys Using In-Situ Scanning Electron Microscopy". MRS Advances 5, n. 29-30 (2020): 1603–11. http://dx.doi.org/10.1557/adv.2020.190.
Testo completoAbstract (sommario):
ABSTRACTWe describe experimental approaches to real time examination of the microstructural evolution of Ti 6%Al 4%V upon cooling from above the beta transus (~995 °C) while imaging in the scanning electron microscope. Ti 6%Al 4%V is a two phase, α+β titanium alloy with high strength and corrosion resistance. The β →α transformation on cooling can give rise to different microstructures and properties through various thermal treatments. Fully lamellar microstructures, bi-modal microstructures, and equiaxed microstructures can each be obtained by accessing different cooling rates upon the final treatment above the beta temperature, each resulting in uniquely enhanced material properties.Utilizing the capabilities of a heating/ tensile stage developed by Kammrath & Weiss Inc., are able to apply real-time imaging techniques in the scanning electron microscope to monitor the development of the microstructure. Annealing temperatures up to 1100 °C are attainable, with cooling rates ranging from 0.1 ° C per second to 3.3 °C per second. This has allowed us to directly observe the formation of lamellae at different annealing temperature/ cooling rate combinations to determine the lamellar microstructure width, separation, and colony size.
19
Khodabakhshi, Farzad, Mohsen Kazeminezhad, Mohammad Azarnush e Seyyed Hossein Miran. "Effect of Post Annealing Treatment on Nano-Structured Low Carbon Steel Sheets Processed by Constrained Groove Pressing". Materials Science Forum 667-669 (dicembre 2010): 1009–14. http://dx.doi.org/10.4028/www.scientific.net/msf.667-669.1009.
Testo completoAbstract (sommario):
There are many works on annealing process of SPDed bulk metals but there are limited works on annealing process of SPDed sheets. Therefore, in this study the annealing response after constrained groove pressing (CGP) of low carbon steel sheets has been investigated. These sheets are subjected to severe plastic deformation at room temperature by CGP method up to three passes. Nano-structured low carbon steel sheets produced by severe plastic deformation are annealed at temperature range of 100 to 600 °C for 20 min. The microstructural changes after deformation and annealing are studied by optical microscopy. The effects of CGP strain and annealing temperature on microstructure, strength and hardness evolutions of the nano-scale grained low carbon steel are examined. The results show that annealing phenomena can effectively improve the elongation of process sheets with preserving the hardness and mechanical strength. Also, a thermal stability of microstructure can be observed with annealing at a temperature range of 375–425 °C and 400 °C is achieved as an optimum annealing temperature. Microstructure after post-annealing at temperatures of higher than 600 °C shows abnormal grain growth.
20
Arlazarov, Artem, Jean Marc Pipard, Nora Kabou, Pierre Targy e Marc Olivier Thénot. "Towards High Strength-Ductility Balance Using Double Annealing Cycles". Materials Science Forum 1105 (29 novembre 2023): 179–84. http://dx.doi.org/10.4028/p-od7cfl.
Testo completoAbstract (sommario):
Impact of first annealing on the formation and evolution of the microstructure during second annealing and on the final mechanical properties was investigated. Simple Fe-C-Mn-Si steel was used in this study. Dilatometry tests coupled with metallographic examinations were carried out to monitor the evolution of phase transformations and associated microstructure. Difference in the austenite evolution between simple and double annealing was highlighted. Based on the obtained results, conditions were selected for the annealing trials on bigger sample. Mechanical properties of heat-treated steels were assessed through the standard tensile tests. Double annealing treatment resulted in a better strength-ductility balance and in a good stability against soaking and quenching temperature variation. Complex ultra-fine multiphase microstructure containing at least 5 different microstructural constituents was revealed and observed using Scanning Electron Microscopy. As well, retained austenite fraction was estimated through magnetization saturation method.
21
Yang, Yi Qiao, Shuang Jiang e Xiang Zhao. "Microstructure Evolution of Laser Direct Metal Deposition of M2 High Speed Steel". Materials Science Forum 879 (novembre 2016): 2198–203. http://dx.doi.org/10.4028/www.scientific.net/msf.879.2198.
Testo completoAbstract (sommario):
In the current investigation, the M2 high speed steel (HSS) sample was produced by laser direct metal deposition (DMD) with a rapid manufacturing (AM) process. The overall microstructure analysed by light optical microscopy (LOM) was a gradual transition from bottom zone to top zone due to the continuous decrease of the cooling rate. The observed microstructure from SEM and XRD was consisted of a cellular or dendritic structure of ferrite, martensite, retained austenite and fine carbides. Annealing at 860 oC led to spheroidization of carbides. The carbides were examined by XRD to be M6C and MC. With prolonging the annealing holding time, the more homogenous microstructure could be acquired. These studies demonstrated that annealing can improve microstructures of M2 HSS produced by DMD.
22
Torganchuk, Vladimir, Dmitri A. Molodov, Andrey Belyakov e Rustam Kaibyshev. "Microstructure and Mechanical Properties of an Ultrafine Grained Medium-Mn Steel". Defect and Diffusion Forum 385 (luglio 2018): 308–13. http://dx.doi.org/10.4028/www.scientific.net/ddf.385.308.
Testo completoAbstract (sommario):
The effect of cold working followed by annealing on the development of ultrafine grained microstructure and mechanical properties of an Fe-12%Mn-0.6%C-1.5%Al medium-manganese steel was studied. The steel was cold rolled with intermediate annealings and then annealed at 873 K or 923 K for 30 min. The yield strength and total elongation of the Fe-12Mn-0.6C-1.5Al steel after cold rolling were 1200 MPa and 14%, respectively. The heat treatments resulted in the formation of two phase (austenite-ferrite) ultrafine grained microstructures with average grain sizes of 0.9 to 1.2 μm, depending on the annealing temperature. The annealed ultrafine grained steel samples exhibit the yield strength in the range of 800-950 MPa, the ultimate tensile strength in the range of 1150-1200 MPa, and total elongation of 12% to 19%.
23
Nes, Erik, Bjørn Holmedal e Børge Forbord. "The Effect of Boundary Structure on the Mechanical Properties of Aluminium Alloys". Materials Science Forum 519-521 (luglio 2006): 63–70. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.63.
Testo completoAbstract (sommario):
The microstructure in heavily deformed metals can be characterized as a complex “mixture” of low and high angle boundaries. By careful annealing of such cold deformed conditions, ultra-fine grained materials can be obtained. This phenomenon has been known for long and utilised in the production of special aluminium sheet qualities, and has received new interest with the emergence of the equal channel angular pressing (ECAP) technique. This work reviews the mechanical properties resulting from plastic deformation and annealing of aluminium, looking at alloys which prior to annealing was subjected to both severe plastic deformation (ECAP) and more conventional deformation by cold rolling. The effect of the resulting microstructures on the subsequent work hardening properties are model, applying the new microstructural metal plasticity model (MMP-model) developed in Trondheim over the last decade.
24
Lee, Dong Hae, Mahoto Takeda, Masaki Takeguchi e Dong Sik Bae. "Precipitation Behavior and Magnetic Properties of Nanoscale Particles in a Cu–10 at% Ni–5 at% Co Alloy". Advanced Materials Research 1077 (dicembre 2014): 23–29. http://dx.doi.org/10.4028/www.scientific.net/amr.1077.23.
Testo completoAbstract (sommario):
We investigated the relationship between the microstructure and magnetic properties of a Cu–10 at% Ni–5 at% Co alloy by using a transmission electron microscope (TEM), a SQUID magnetometer and a magnetic thermo–balance. TEM observations were performed to examine the microstructures of the Cu–Ni–Co specimens annealed at four temperatures between 873 K and 1073 K below and above the Curie point (983 K).Particles with cubic shapes were linearly arranged along the <100> direction of the copper matrix in specimens prepared by isothermal annealing at temperatures below the Curie point, while octahedral precipitates were sparsely formed by annealing above the Curie point. The TEM observations confirmed that the microstructural evolution in the Cu–Ni–Co specimens isothermally annealed at 1023 K. Although coherent cubic particles appeared at the initial stage of annealing, incoherent precipitates were finally formed with increased annealing time at 1023 K. The present SQUID measurements indicated that the curve of coercive force vs. annealing time had a peak at a short annealing period.
25
Rocha, Roberta O., Tulio M. F. Melo e Dagoberto Brandao Santos. "Influence of Continuous Annealing Conditions on the Microstructure and Mechanical Properties of a C-Mn Dual Phase Steel". Materials Science Forum 638-642 (gennaio 2010): 3479–84. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.3479.
Testo completoAbstract (sommario):
The influence of continuous annealing variables on the microstructure and mechanical properties of a C-Mn Dual Phase (DP) steel was studied. The annealing cycles were simulated using a Gleeble machine. Some specimens were quenched at different stages of the annealing cycle in order to evaluate the microstructural evolution during the annealing process. Tensile tests and microstrutural analysis were carried out. The results showed that high heating rates increased the final recrystallization temperature and as a consequence the microstructure obtained was refined. Austenite grain nucleation and growth were also influenced by the heating rates. Soaking temperature was the most influent variable on the mechanical properties, i. e., the yield strength increased and the tensile strength decreased with an increase in the soaking temperature. Microstructural analysis showed that not only martensite, but also bainite and martensite-retained autenite constituent (MA) were formed. Undissolved carbides were also detected by transmission electron microscopy.
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Ruckmich, Stefan. "Influence of Microstructure and Impurities on Thermal Conductivity of Aluminium Nitride Ceramics". International Journal of Materials Research 92, n. 7 (1 luglio 2001): 839–44. http://dx.doi.org/10.1515/ijmr-2001-0152.
Testo completoAbstract (sommario):
Abstract The microstructure of AlN ceramics, which were pressureless sintered with CaO and CaF2 as additives, was modified via an annealing process. The thermal conductivity of these samples was measured and correlated with the microstructure changes. The influence of the microstructural elements, especially content and distribution of secondary phases, is described and quantitatively related to mixture models from literature for a full understanding of the relationships between microstructure, impurity content and thermal conductivity. The main result of the investigation is that the microstructural influence on thermal conductivity is limited to at maximum 41 W/m · K. The increase of the intrinsic thermal conductivity, due to loss of impurities especially oxygen during the beginning of the annealing process, is the main effect influencing thermal conductivity of sintered samples.
27
Zhu, Lei, Ying Yang, Yuyang Li, Huanhuan Xuan, Hongtao Chen, Yanxiang Zhang e Mufu Yan. "Effect of Initial Microstructure on Soft Annealing of a Low-Carbon Bainitic Steel". Materials Proceedings 3, n. 1 (18 febbraio 2021): 6. http://dx.doi.org/10.3390/iec2m-09246.
Testo completoAbstract (sommario):
A low-carbon bainitic tool steel exhibiting high hardness after hot rolling typically has poor machinability. To soften this type of steel and to accelerate the soft annealing process, an austenitizing step was designed based on thermodynamic calculations of phase stability and introduced prior to the annealing step. Different initial microstructures were prepared by three austenitizing temperatures (680 °C, 850 °C, 1000 °C) and three cooling methods (water quenching, oil quenching, and air cooling). The effect of initial microstructure on microstructures and hardness was studied. Softening equations, a function of annealing temperature and time, were established for different initial microstructures, and the relationships between annealing temperature, annealing time, activation energy, and hardness were explored. The predicted hardness was consistent with the measured values. Martensitic structure has a low activation energy for diffusion and a higher softening rate compared to that of the bainitic structure. In addition, the higher the carbide content in the bainitic structure, the smaller the activation energy tended to be.
28
Mostafapour, Amir, Vahid Rezazadeh e Salar Salahi. "Effect of Annealing Heat Treatment on the Microstructural Refinement of Pure Copper by Friction Stir Processing". Advanced Materials Research 829 (novembre 2013): 131–35. http://dx.doi.org/10.4028/www.scientific.net/amr.829.131.
Testo completoAbstract (sommario):
Recently, friction stir processing (FSP) was developed as an effective method to modify microstructural and mechanical properties of materials. During process, a rotating tool is inserted in a plate, providing frictional heating and mechanical mixing. In this investigation, the effect of annealing heat treatment on the microstructure characteristics of the nugget zone was investigated during friction stirs processing (FSP) of the pure copper. Plate with 4 mm thickness was friction stir processed at constant traverse speed of 45 mm/min and tool rotation speed of 700 rpm. Samples were processed in various annealing conditions. Results showed that by increasing the annealing duration from 45 to 180 minutes at annealing temperatures of 600°C and 800°C, the grain size and the hardness value of samples significantly decreased. At annealing temperature of 1000°C samples were exposed to extra heat, grains started to coarsen and hardness decreased. Ultrafine-grained microstructure in FSP samples was achieved using annealing heat treatment at annealing temperature of 600°C.
29
Ajami Ghaleh Rashidi, Padina, Hossein Arabi e Seyed Mehdi Abbasi. "An assessment of static recrystallization in L-605 Cobalt-based superalloy". Metallurgical and Materials Engineering 22, n. 4 (31 dicembre 2016): 221–36. http://dx.doi.org/10.30544/231.
Testo completoAbstract (sommario):
In this research, the effect of cold rolling, annealing time and temperature on microstructure and hardness were studied in L-605 superalloy. A cast bar of L-605 alloy was hot rolled at 1200ºC. As the following, it was solutionized at 1230 ºC for 1 hour and finally was cold rolled by different amounts (i.e. 5-35 percent thickness reduction). The cold-rolled samples were heat treated for different times (i.e. 2-120 min.) at temperature range of 1068-1230 ºC in order to study their recrystallization behavior. The results of microstructural analysis indicated that static recrystallization is responsible for microstructural refinement and coarsening, so that an increase in the amounts of cold rolling resulted in a fully recrystallized microstructure at lower temperature. This analysis also indicated that annealing temperature is more effective than annealing time in grain growth. Microstructural evaluation as well as showed that carbides such as M7C3 and M23C6 which have been reported in some literature were not observed during rolling or annealing in this research. It is perhaps due to usage of high annealing temperatures or possibly due to their very low contents which was not possible for us to evaluate their formation with conventional methods. Hardness results revealed that higher annealing temperature lead to lower hardness values as expected.
30
Akbari, G. H., H. Abbaszadeh e H. Ghotbi Ravandi. "Effects of Al, Si and Mn on the Recrystallization Behaviors of Fe Containing 70B Brass". Materials Science Forum 558-559 (ottobre 2007): 107–11. http://dx.doi.org/10.4028/www.scientific.net/msf.558-559.107.
Testo completoAbstract (sommario):
The effects of alloying elements and impurities on the microstructure and properties of metals and alloys are important. Understanding of these effects may help to control and produce products with desired properties at lower cost. In the present work the effects of Al, Si and Mn on the recrystallization behavior, hardness and microstructural changes of an Fe- containing brass during annealing were studied. The results show that alloying elements strongly affect recrystallization kinetics and resulted finer microstructures. Hardness variations during annealing are consistent with microstructural observations and the presence of alloying elements. All elements slow down recrystallization progress and increase resulted hardness values. The resulted microstructures in the presence of alloying elements are much finer than that of plain 70B brass. It was concluded that the present alloying elements affect the recrystallization behavior of 70B brass in a similar manner. Their mechanism of interactions is solute drag effect and their effects sum up when they present together.
31
Pan, Hai Bin, Yuan Tian, Guang Gui Cheng e Li Qiang Guo. "Experimental Investigation of the Impact of Annealing on Resistivity of Boron-Doped Hydrogenated Nanocrystalline Silicon Thin Films". Applied Mechanics and Materials 29-32 (agosto 2010): 1883–87. http://dx.doi.org/10.4028/www.scientific.net/amm.29-32.1883.
Testo completoAbstract (sommario):
Boron-doped hydrogenated nanocrystalline silicon (nc-Si:H) thin films were deposited by plasma enhanced chemical vapor deposition (PECVD). Microstructures of these films were characterized and analyzed by Raman spectrum and atomic force microscopy (AFM). Thickness and resistivity of these films was measured by high-resolution profilometer and four-point probe respectively. The impact of annealing on boron-doped nc-Si:H thin films’ resistivity and the relationship between resistivity and microstructure were investigated. The results show that annealing and the annealing temperature have great impact on resistivity of nc-Si:H thin films as a result of microstructures changing after annealing. Resistivity of nc-Si:H thin films decreases after annealing, but it rises with the increasing annealing temperature in the range of 250°C to 400°C.
32
Storojeva, L., D. Ponge, D. Raabe e R. Kaspar. "On the influence of heavy warm reduction on the microstructure and mechanical properties of a medium-carbon ferritic –pearlitic steel". International Journal of Materials Research 95, n. 12 (1 dicembre 2004): 1108–14. http://dx.doi.org/10.1515/ijmr-2004-0201.
Testo completoAbstract (sommario):
Abstract The current study on a medium-carbon steel (0.36% C) with deformation-induced spheroidized cementite produced by heavy warm deformation (HWD) was carried out in order to investigate an alternative microstructural route when compared to conventional quenching and tempering (QT) or soft annealing (SA) processes. After austenite deformation, the HWD samples were cooled and heavily deformed at temperatures below the γ–α transformation followed by a simulated coiling treatment. In particular, the study addresses the influence of adiabatic heating due to the heavy deformation on the microstructure and properties. The mechanical properties after the various treatments show that the strength – ductility relation after HWD and QT are superior to those after continuous cooling (CC) or soft annealing (SA). In the microstructures obtained from the CC and SA treatments we observed lamellar pearlite which deteriorated the mechanical properties. A similar effect was observed after the adiabatic HWD treatment, which also entails some lamellar pearlite. HWD at 670 °C with subsequent coiling produced a microstructure with dispersed spheroidized cementite distributed homogeneously in the fine-grained ferrite matrix. The mechanical properties of the HWD samples are well comparable to those observed after the QT process owing to the resemblance in microstructure.
33
Dong, Yan, Bo Ping Zhang, Ya Ru Zhang e Jing Feng Li. "Microstructure and Dielectric Properties of LiTiNiO Thin Films". Key Engineering Materials 336-338 (aprile 2007): 2635–38. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.2635.
Testo completoAbstract (sommario):
LiTiNiO thin films were deposited on Pt/Ti/SiO2/Si(100) substrates using a sol-gel spin-coat method. The effects of annealing temperature and annealing time on microstructures and dielectric properties of the thin films were investigated. SEM images showed the thin films had uniform and dense microstructure and the grain size increased with increasing temperature and time. The LiTiNiO thin films consisted of complex oxides which proportions were mainly dependent on the annealing condition. The LiTiNiO thin film annealed at 600°C for 1h showed the highest dielectric constant and frequency stability, while prolonging annealing time even at 600°C resulted in the decrease in the frequency stability of the dielectric constants.
34
Gaggiotti, Matteo, Luciano Albini, Paolo Emilio Di Nunzio, Andrea Di Schino, Giulia Stornelli e Giulia Tiracorrendo. "Ultrafast Heating Heat Treatment Effect on the Microstructure and Properties of Steels". Metals 12, n. 8 (5 agosto 2022): 1313. http://dx.doi.org/10.3390/met12081313.
Testo completoAbstract (sommario):
The adoption of the ultrafast heating (UFH) process has gained much attention in the last few years, as the green energy and minimization of CO2 emissions are the main aspects of contemporary metal science and thermal treatment. The effect of ultrafast heating (UFH) treatment on carbon steels, non-oriented grain (NGO) electrical steels, and ferriticor austenitic stainless steels is reported in this review. The study highlights the effect of ultrarapid annealing on microstructure and textural evolution in relation to microstructural constituents, recrystallization temperatures, and its effect on mechanical properties. A strong influence of the UFH process was reported on grain size, promoting a refinement in terms of both prior austenite and ferrite grain size. Such an effect is more evident in medium–low carbon and NGO steels than that in ferritic/austenitic stainless steels. A comparison between conventional and ultrafast annealing on stainless steels shows a slight effect on the microstructure. On the other hand, an evident increase in uniform elongation was reported due to UFH. Textural evolution analysis shows the effect of UFH on the occurrence of the Goss component (which promotes magnetic properties), and the opposite with the recrystallization g-fiber. The recovery step during annealing plays an important role in determining textural features; the areas of higher energy content are the most suitable for the nucleation of the Goss component. As expected, the slow annealing process promoted equiaxed grains, whereas rapid heating promoted microstructures with elongated grains as a result of the cold deformation.
35
Delić, Alen, Mirsada Oruč, Milenko Rimac, Almaida Gigović-Gekić e Raza Sunulahpašić. "The influence of solution annealing on microstructure and mechanical properties heat-resistant cast Steel HK30 modified by Niobium". Metallurgical and Materials Engineering 25, n. 3 (16 ottobre 2019): 237–45. http://dx.doi.org/10.30544/430.
Testo completoAbstract (sommario):
In this paper, the room temperature mechanical properties, as well as the microstructure of HK 30 Nb steel, were tested in the initial as-cast and solution annealed condition. Results show that tensile properties after the solution annealing have a slightly lower value than as-cast samples. Microstructural analysis of samples after solution annealing showed dissolution of primary carbides present in the initial as-cast condition. The morphology and composition of carbides were changed during a solution annealing. Analysis of microstructure was done by optical microscopy (OM) and scanning electron microscope (SEM), whereas hardness and tensile tests were performed for characterization of mechanical properties.
36
Polozov, Igor, Kirill Starikov, Anatoly Popovich e Vadim Sufiiarov. "Mitigating Inhomogeneity and Tailoring the Microstructure of Selective Laser Melted Titanium Orthorhombic Alloy by Heat Treatment, Hot Isostatic Pressing, and Multiple Laser Exposures". Materials 14, n. 17 (30 agosto 2021): 4946. http://dx.doi.org/10.3390/ma14174946.
Testo completoAbstract (sommario):
Titanium orthorhombic alloys based on intermetallic Ti2AlNb-phase are attractive materials for lightweight high-temperature applications. However, conventional manufacturing of Ti2AlNb-based alloys is costly and labor-consuming. Additive Manufacturing is an attractive way of producing parts from Ti2AlNb-based alloys. High-temperature substrate preheating during Selective Laser Melting is required to obtain crack-free intermetallic alloys. Due to the nature of substrate preheating, the temperature profile along the build height might be uneven leading to inhomogeneous microstructure and defects. The microstructural homogeneity of the alloy along the build direction was evaluated. The feasibility of mitigating the microstructural inhomogeneity was investigated by fabricating Ti2AlNb-alloy samples with graded microstructure and subjecting them to annealing. Hot isostatic pressing allowed us to achieve a homogeneous microstructure, eliminate residual micro defects, and improve mechanical properties with tensile strength reaching 1027 MPa and 860 MPa at room temperature and 650 °C, correspondingly. Annealing of the microstructurally graded alloy at 1050 °C allowed us to obtain a homogeneous B2 + O microstructure with a uniform microhardness distribution. The results of the study showed that the microstructural inhomogeneity of the titanium orthorhombic alloy obtained by SLM can be mitigated by annealing or hot isostatic pressing. Additionally, it was shown that by applying multiple-laser exposure for processing each layer it is possible to locally tailor the phase volume and morphology and achieve microstructure and properties similar to the Ti2AlNb-alloy obtained at higher preheating temperatures.
37
Hitit, Aytekin, Ziya Ozgur Yazici, Hakan Şahin, Pelin Öztürk, Buğrahan Eryeşil e Nusrettin Barut. "Microstructure and Mechanical Properties of CoWB Based Composites Produced by Crystallization of Ni-Co-Zr-Ta-W-B Bulk Metallic Glass". Metals 12, n. 2 (28 gennaio 2022): 251. http://dx.doi.org/10.3390/met12020251.
Testo completoAbstract (sommario):
CoWB based composites were produced by annealing Ni33.6Co23.2Zr0.5Ta4W23.7B15 bulk metallic glass above the crystallization temperature. The effect of annealing on the microstructure of the composites was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microhardness (Hv) and indentation fracture toughness (KC) of the composites were also measured. Microstructural examinations revealed that the first precipitated phase as a result of annealing is a nickel solid solution. As the annealing time is increased, CoWB and the nickel solid solution begins to precipitate. If the annealing time is increased further, the CoWB remains stable, while the nickel solid solution transforms into Ni3Ta. The microhardness of the as-cast alloy was determined to be 1190 HV. As a result of annealing, composites with a microhardness of around 1400 HV were obtained due to the precipitation of CoWB. KC of the composite with the maximum hardness was determined to be ~3 MPa.m1/2. The effect of microstructure on the mechanical properties of the composites is discussed.
38
Stopyra, Michał, e Janusz Adamiec. "Microstructural Stability of Long-Term Annealed AZ91 Magnesium Alloy Weld Joint". Materials Science Forum 782 (aprile 2014): 161–65. http://dx.doi.org/10.4028/www.scientific.net/msf.782.161.
Testo completoAbstract (sommario):
Welding and pad welding are widely used methods of repair and regeneration of defective magnesium alloys castings. AZ91 is one of the most popular magnesium alloys used at temperature up to 120°C. Therefore there is need to study the influence of welding and elevated temperature exposure on the microstructure and properties of AZ91 weld joints. This paper discusses microstructural stability of AZ91 gas tungsten arc weld joint in T6 condition (solution treated and aged). In order to examine the weld joints microstructural stability, the long-term annealing has been carried out at 120°C. Hardness of the base metal and fusion weld was measured after 250, 500, 750 and 1000h exposure respectively. Additionally, the base metals and the welds microstructure after 1000h annealing was investigated. Both in the base metal and in the weld, long-term annealing caused decrease in the intermetallic phases volume fraction. However, neither phase composition nor hardness of the weld joint were influenced by the heat treatment. Based on these results, it could be stated that the microstructure of investigated weld joint is stable at working temperature.
39
Sankaran, S., e Satyam Suwas. "Texture Evolution in Thermomechanically Control Processed Multiphase Medium Carbon Microalloyed Steel: Forged, Rolled and Low Cycle Fatigued Microstructures". Materials Science Forum 702-703 (dicembre 2011): 449–52. http://dx.doi.org/10.4028/www.scientific.net/msf.702-703.449.
Testo completoAbstract (sommario):
A ferrite-bainite-martensite (F-B-M) microstructure was produced in a medium carbon microalloyed steel through two routes, namely, low temperature finish forging or rolling, followed by a two step cooling and annealing. The texture formed in control forged and rolled material after two step cooling followed by annealing (TSCA) was examined. Texture investigation was also carried out after low cycle fatigue testing at low and high total strain amplitudes. Transmission electron microscopy was employed to study the microstructural evolution. Fatigue tested F-B-M microstructure obtained through the rolling route was stable up to a total strain amplitude of 0.6%. This paper reports the evolution of texture and microstructure in two-step cooled F-B-M microstructure and their stability during fatigue loading.
40
Huang, Guang Jie, Ling Yun Wang, Guang Sheng Huang, Fu Sheng Pan e Qing Liu. "Effect of Rolling and Annealing on the Mechanical Properties and Microstructure of AZ31 Magnesium Alloy". Materials Science Forum 546-549 (maggio 2007): 379–82. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.379.
Testo completoAbstract (sommario):
Microstructural evolution and mechanical properties of the AZ31 magnesium alloy during rolling and annealing process were investigated. The sheet samples were prepared after different stages of the hot rolling, cold rolling and annealing processes. The hot rolling temperature was between 300-450C and the final thickness of the cold rolled sheets was 1.5mm. The cold rolled sheets were annealed at different annealing temperature (260-350C) for different time (10~120min). Tensile test was performed to investigate the mechanical properties of the samples obtained from different stages. With aid of the optical microscopy, scanning electron microscopy (SEM) techniques, the microstructure of the samples were characterized and the results were related to the mechanical properties. It was found the hot-rolled sheets exhibit higher ductility comparing with the cold-rolled sheets. The microstructural investigation showed that the microstructure of the hot-rolled samples was dominated by recrystallized equiaxed grains while the microstructure of the cold-rolled samples dominated by deformation twining. By applying annealing on the cold-rolled sheets, fine recrystallization grains were obtained and ductility of the samples was improved. The effects of the grain size and twining on mechanical properties of the AZ31 sheet were further discussed based on the experimental results.
41
Azevedo, G., Ronaldo Barbosa, Elena V. Pereloma e Dagoberto Brandão Santos. "Intercritical Annealing Behaviour of an Ultrafine Grained C-Mn Steel Obtained by Hot Torsion Deformation". Materials Science Forum 550 (luglio 2007): 471–76. http://dx.doi.org/10.4028/www.scientific.net/msf.550.471.
Testo completoAbstract (sommario):
Several studies concerning ferrite grain refinement have been developed in recent the last years due to the recognised influence of such microstructures on steels properties. This work was focused on the evaluation of the microstructure and mechanical properties of an ultrafine grained CMn steel obtained by hot torsion deformation and intercritical annealing. After 5 min soaking at 900 and 1200°C, the samples of low carbon steel were quenched and then reheated. Hot torsion deformation was conducted at temperatures of 700 or 740°C. The torsion schedule consisted of 7 isothermal passes leading to a total true strain of ≈1 and generating an ultrafine and inhomogeneous microstructure with grain sizes of the order of 1-m, formed by strain-induced dynamic transformation (SIDT). The samples were heated up to 800oC and held for 1, 2 and 3 h. A more homogeneous microstructure and ferrite grain size were obtained after annealing The microhardness tests showed the reduction in hardness with the increase in annealing time. They also highlighted the effects of the ferrite grain size and the volume fractions of the microstructure constituents.
42
Lim, Chao Voon Samuel, Yang Liu, Chen Ding e Aijun Huang. "Effect of Supra-Transus Deformation Conditions on Recrystallization of Beta Ti Alloy". Metals 11, n. 8 (12 agosto 2021): 1278. http://dx.doi.org/10.3390/met11081278.
Testo completoAbstract (sommario):
There is increasing usage of high strength Beta Ti alloy in aerospace components. However, one of the major challenges is to obtain homogeneous refined microstructures via the thermo-mechanical processing. To overcome this issue, an understanding of the hot deformation conditions effect on the microstructure, prior to and after annealing, is needed. In this work, the effect of strain levels, which is more precise than percentage of reduction, and strain rate under supra-transus deformation temperature on beta annealing are studied using a double cone sample. The Electron Backscattered Diffraction (EBSD) is used to determine the deformed microstructure and texture evolution, as well as the static recrystallized grains evolution using the ex situ annealing approach. This work provides evidence that the mechanisms of dynamic recovery and recrystallization, along with texture evolution, are affected by the deformation conditions, which in turn affected the subsequent static recrystallization during annealing. It will also be shown that high levels of strain do not necessarily lead to an increase in the rate of recrystallization. Finally, the results obtained provided several examples of guidance in designing the TMP processes for obtaining not only a refine microstructure, but a more homogeneous beta microstructure during the beta processing of Beta Ti alloy.
43
Rodak, Kinga, e Krzysztof Radwański. "Structural Stability of Cu Processed by Severe Plastic Deformation Method". Solid State Phenomena 163 (giugno 2010): 114–17. http://dx.doi.org/10.4028/www.scientific.net/ssp.163.114.
Testo completoAbstract (sommario):
The annealing behaviour of monocrystaline Cu processed by Cyclic Extrusion Compression (CEC) was investigated. The effect of the CEC strain on the annealing behaviour of submicrometer grained structure was studied by examination of the microstructural changes of the samples processed by two different CEC strains, 4.8 and 13.9 during annealing at 300oC for the time in the range from 1sec to 120 min. The results show that microstructure is stable up to an annealing time of 15 min. At a higher time of annealing (above 15 min), a gradual grain growth occurs.
44
Xing, Q., X. Huang e Niels Hansen. "Microstructural Coarsening during Annealing of Cold Rolled Aluminum". Materials Science Forum 467-470 (ottobre 2004): 209–16. http://dx.doi.org/10.4028/www.scientific.net/msf.467-470.209.
Testo completoAbstract (sommario):
The microstructural evolution during annealing below the recrystallization temperature of a commercial purity aluminum (99wt.% purity) cold rolled to a true strain of 2 has been investigated by transmission electron microscopy concentrating on microstructural and orientational aspects. The deformation microstructure was a typical lamellar structure with extended lamellar boundaries, GNBs (geometrical necessary boundaries), and short interconnecting boundaries, IDBs (incidental dislocation boundaries). The microstructure was divided into regions representing typical rolling texture orientations and regions of other orientations. During annealing the structure coarsened towards an equiaxed structure and it was observed that this coarsening was significantly slower in regions of rolling texture orientations than in regions of other orientations. This difference was discussed based on the characteristics of the deformation structure.
45
Qin, Lanlan, Changjun Chen, Min Zhang, Kai Yan, Guangping Cheng, Hemin Jing e Xiaonan Wang. "The microstructure and mechanical properties of deposited-IN625 by laser additive manufacturing". Rapid Prototyping Journal 23, n. 6 (17 ottobre 2017): 1119–29. http://dx.doi.org/10.1108/rpj-05-2016-0081.
Testo completoAbstract (sommario):
Purpose Laser additive manufacturing (LAM) technology based on powder bed has been used to manufacture complex geometrical components. In this study, IN625 superalloys were fabricated by high-power fiber laser without cracks, bounding errors or porosity. Meanwhile, the objectives of this paper are to systemically investigate the microstructures, micro-hardness and the precipitated Laves phase of deposited-IN625 under different annealing temperatures. Design/methodology/approach The effects of annealing temperatures on the microstructure, micro-hardness and the precipitated Laves phase were studied by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), selected area electron diffraction (SAED), backscattered electron (BSE) imaging in the SEM and transmission electron microscopy (TEM), respectively. The thermal stability of the dendritic morphology about IN625 superalloys was investigated through annealing at temperatures range from 1,000°C to 1,200°C. Findings It is found that the microstructure of deposited-IN625 was typical dendrite structure. Besides, some Laves phase precipitated in the interdendritic region results in the segregation of niobium and molybdenum. The thermal stability indicate that the morphology of dendrite can be stable up to 1,000°C. With the annealing temperatures increasing from 1,000 to 1,200°C, the Laves phase partially dissolves into the γ-Ni matrix, and the morphology of the remaining Laves phase is changing from irregular shape to rod-like or block-like shape. Research limitations/implications The heat treatment used on the IN625 superalloys is helpful for knowing the evolution of microstructures and precipitated phases thermal stability and mechanical properties. Practical implications Due to the different kinds of application conditions, the original microstructure of the IN625 superalloys fabricated by LAM may not be ideal. So exploring the influence of annealing treatment on IN625 superalloys can bring theory basis and guidance for actual production. Originality/value This study continues valuing the fabrication of IN625 by LAM. It shows the effect of annealing temperatures on the shape, size and distribution of Laves phase and the microstructures of deposited-IN625 superalloys.
46
Li, Xiao Ling, Wei Liu, Andrew Godfrey e Qing Liu. "Effect of an Electric Field on the Texture and Microstructure Evolution during Annealing of High Reduction Cold-Rolled Ni". Key Engineering Materials 353-358 (settembre 2007): 679–82. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.679.
Testo completoAbstract (sommario):
The influence of an electric field on the annealing of high purity (99.999%) cold rolled nickel has been investigated. Annealing was carried out for 2 hours at temperatures between 300oC and 800oC with and without an electric field of strength 2.0KVcm-1. The microstructure and fraction of cube texture resulting were characterized using electron backscattering pattern (EBSP) technique. Annealing in an electric field leads to somewhat smaller average values of the cube fraction and grain sizes compared to annealing without an electric field. The highest temperature (800oC) annealing in an electric field results in microstructures with a lower fractional twin boundary length.
47
Han, Fang, Hanxi Wang, Xuan Luo, Ziyong Hou, Guilin Wu e Xiaoxu Huang. "Microstructure and Texture Evolution of Hot-Rolled Mg-3Gd Alloy during Recrystallization". Metals 13, n. 7 (30 giugno 2023): 1216. http://dx.doi.org/10.3390/met13071216.
Testo completoAbstract (sommario):
An Mg-3Gd (wt.%) sample with gradient rolling strains (ε = 0–0.55) was prepared using a wedge-shaped plate after one-pass hot rolling, allowing a high-throughput characterization of microstructure and texture over a wide strain range within one hot-rolled plate. The microstructure and texture evolutions were characterized as a function of rolling strain for the as-hot-rolled sample and as a function of annealing temperature for the subsequently annealed samples. The deformed microstructure showed a gradual change with increasing rolling strain, i.e., from a deformation twins-dominant structure in the low strain range of 0–0.20, to a shear bands-dominant structure in the higher strain range of 0.20–0.55. The recrystallization behavior during annealing showed a clear correlation between the recrystallization nucleation site and the deformed microstructure. However, a weak recrystallization texture with non-basal texture components was formed over almost the entire strain range. This work demonstrates a high-throughput experimental strategy using a wedge-shaped sample to investigate the effect of various processing parameters, such as strain and annealing temperature, on the evolution of microstructure, texture, and mechanical properties, which could accelerate the optimization of processing parameters and microstructural design.
48
Ghaderi, Alireza, Peter D. Hodgson e Matthew R. Barnett. "Microstructure and Texture Development in Ti-5Al-5Mo-5V-3Cr Alloy during Cold Rolling and Annealing". Key Engineering Materials 551 (maggio 2013): 210–16. http://dx.doi.org/10.4028/www.scientific.net/kem.551.210.
Testo completoAbstract (sommario):
This study focuses on the microstructure and texture evolution of a Ti-5Al-5Mo-5V-3Cr alloy during cold rolling and annealing treatments. Three samples with different initial microstructures were cold rolled to a 40% reduction in thickness. The starting microstructure of one sample was single β phase while two other specimens were α+β phases with different α particle sizes, distributed in β grains. For all three samples, the average size of primary β grains was 150 µm. The cold rolled specimens were then annealed at 860 °C (10 °C above the β transus temperature) for 5 minutes followed by water quenching. Microstructure development during cold rolling and recrystallization was studied by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) technique. Microstructure investigations showed that massive amount of shear bands occurred during the cold rolling of the single β phase sample while only a few shear bands were observed in the α+β cold rolled microstructures. The cold rolled texture of the sample comprised of a single β phase contains a gamma fibre (//ND) and a partial alpha fibre (//RD). Annealing treatment decreased the intensity of the cold rolled texture in the single β phase sample. Also, it was found that the presence of α precipitates changes the common annealing texture observed in the single β phase specimen.
49
Zhuang, Yan-Xin, Xiu-Lan Zhang e Xian-Yu Gu. "Effect of Annealing on Microstructure and Mechanical Properties of Al0.5CoCrFeMoxNi High-Entropy Alloys". Entropy 20, n. 11 (23 ottobre 2018): 812. http://dx.doi.org/10.3390/e20110812.
Testo completoAbstract (sommario):
The effect of annealing temperature on the microstructure, phase constituents and mechanical properties of Al0.5CoCrFeMoxNi high-entropy complex alloys has been investigated at a fixed annealing time (10 h). The 600 °C-annealing has no obvious effect on their microstructures, while the annealing at 800–1200 °C enhances the precipitation of (Al,Ni)-rich ordered BCC phase or/and (Cr,Mo)-rich σ phase, and thereby greatly affects the microstructure and mechanical properties of the alloys. All the annealed Al0.5CoCrFeNi alloys are composed of FCC and (Al,Ni)-rich ordered BCC phases; the phase constituent of the Al0.5CoCrFeMo0.1Ni alloy changes from FCC + BCC (600 °C) to FCC + BCC + σ (800 °C) and then to FCC + BCC (1100 °C); the phase constituents of the Al0.5CoCrFeMo0.2Ni and Al0.5CoCrFeMo0.3Ni alloys change from FCC + BCC + σ to FCC + BCC with the annealing temperature rising from 600 to 1200 °C; while all the annealed Al0.5CoCrFeMo0.4Ni and Al0.5CoCrFeMo0.5Ni alloys consist of FCC, BCC and σ phases. The phase constituents of most of the alloys investigated are in good agreement with the calculated results from Thermo-Calc program. The alloys annealed at 800 °C under current investigation conditionshave relative fine precipitations and microstructure, and thereby higher hardness and yield stress.
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Fox, G. R., S. B. Krupanidhi, K. L. More e L. F. Allard. "Composition/structure/property relations of multi-ion-beam reactive sputtered lead lanthanum titanate thin films: Part I. Composition and structure analysis". Journal of Materials Research 7, n. 11 (novembre 1992): 3039–55. http://dx.doi.org/10.1557/jmr.1992.3039.
Testo completoAbstract (sommario):
Material properties are greatly dependent upon the structure of the material. This paper, the first of three parts, discusses how composition influences the crystallographic structure and microstructure of lead lanthanum titanate (PLT) thin films grown by the multi-ion-beam reactive sputtering (MIBERS) technique. A transmission electron microscopy (TEM) study detailing the relationship between crystallographic texturing and microstructure development will be presented in a second paper. The dependence of the ferroelectric properties on observed crystallographic structure and microstructure is presented in the third paper of this series. As-deposited PLT microstructures coincide with the structure zone model (SZM) which has been developed to describe the microstructure of thin films deposited by physical vapor deposition. The as-deposited PLT structures are altered during post-deposition annealing as a result of crystallization and PbO evaporation. Amorphous films with more than 10 mole % excess PbO become polycrystalline with porous microstructures after annealing. When there is less PbO in the as-deposited film, 〈100〉 texture and dense structures are observed. Porosity results from PbO evaporation, and 〈100〉 texture is inhibited by excess PbO.