共查询到20条相似文献,搜索用时 53 毫秒
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本工作基于偏析法高纯铝制备的高压电子铝箔,用电子背散射衍射(EBSD)和X射线衍射(XRD)方法研究其在退火过程中的再结晶织构演化,并建立元胞自动机(Cellular automata, CA)模型从能量角度解释不同再结晶机制。实验和模拟结果表明,分级退火时,在低温段变形基体中S型取向({123}〈634〉)和Cu型取向({112}〈111〉)的晶粒通过连续再结晶获得长大优势,立方取向({001}〈100〉)晶粒的形核受到抑制,在后续高温段S型取向和Cu型取向晶粒迅速长大并形成了以S型和Cu型织构为主的再结晶织构;直接高温退火时立方取向晶粒优先形核、长大从而形成强立方织构;CA模型表明两种不同退火条件下的能量差异是造成不同再结晶织构的主要原因。 相似文献
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通过二次冷轧铜棒并850℃恒温热处理,制备出具有较强立方织构的Cu基带。以硝酸银、亚硫酸钠和硫代硫酸钠为主要原料配制镀银液,在立方织构Cu基带上制备出具有较强Ag(200)择优取向的银镀层。在600℃恒温热处理30min后Ag膜仍具有(200)择优取向,而830℃热处理后,Ag会扩散到Cu基底中,重复镀银、热处理5次后,Ag膜具有(200)的择优取向并少量面内织构,所得Ag/立方织构Cu复合带材可作为第二代高温超导带材YBCO涂层导体的金属基底。 相似文献
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介绍了对原APD-10衍射仪PW1078织构附件的改造,建立Bunge符号系统材料织构ODF联机测算系统。对原设备功能开发之后,实现了数据采集、控制、结果打印、图象屏显与绘图,大大地提高了原设备的功能、测算效率与精度。 新建立的ODF联机系统可满足现代材料织构研究的要求,功能不亚于国内外运行的ODF分析系统。该分析系统具有菜单型和反射法只需扫测α从5°~70°等特点。 相似文献
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深冲IF钢再结晶{111}纤维织构形成机制探讨 总被引:3,自引:0,他引:3
为了探讨深冲IF钢再结晶织构与退火温度之间的关系及{111}再结晶织构形成机制,采用X射线衍射三维取向(ODF)和背散射电子衍射(EBSD)分析技术并结合金相组织观察,利用Gibbs-Thom son方程对冷轧IF钢在不同退火温度下的再结晶织构演变规律及形成机制进行研究.实验结果表明:随着退火温度的增加,再结晶量逐渐增多,γ纤维织构强度亦相应增强,同时,α纤维织构强度则逐渐降低;冷轧IF钢再结晶初期的织构转变主要发生在γ纤维织构之间.研究表明,再结晶核心的形成主要以"显微择优形核"为主,晶核的长大则主要以择优生长为主,而Σ重位点阵晶界在再结晶γ纤维织构形成过程中起着重要作用. 相似文献
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为研究GH4169合金楔横轧加工过程中动态再结晶及织构演变规律,采用金相显微镜(OM)和电子背散射衍射(EBSD)对30%,50%两种断面收缩率下GH4169合金楔横轧件表层与心部的微观组织、晶体取向及织构进行分析。结果表明:GH4169合金楔横轧加工过程中,随着动态再结晶的发生,晶体取向逐渐变得随机化分布;轧制表层大角度晶界数量较轧件心部多,轧件表层织构强度变化不大,心部织构强度明显增强;经过楔横轧变形后织构发生转动,原始态织构类型为{001}〈110〉,{111}〈110〉,{111}〈011〉,轧制后主要织构类型为{001}〈010〉,{112}〈110〉,{110}〈111〉,{110}〈112〉;GH4169合金楔横轧件动态再结晶及织构演变规律是由楔横轧特殊变形特点决定的。 相似文献
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Jeong Hun Lee Jong Un Lee Sang-Hoon Kim Seok Weon Song Chong Soo Lee Sung Hyuk Park 《材料科学技术学报》2018,34(10):1747-1755
High-speed rolling (HSR) is known to improve the workability of Mg alloys significantly, which makes it possible to impose a large reduction in a single pass without fracture. In the present study, dynamic recrystallization (DRX) behavior and microstructural and textural variations of Mg alloy AZ31 during a HSR process were investigated by conducting rolling with different imposed reductions in the range of 20%–80% at a high rolling speed of 470 m/min and 400 °C. High-strain-rate deformation during HSR suppresses dislocation slips but promotes twinning, which results in the formation of numerous twins of several types, i.e., {10–12} extension twins, {10–11} and {10–13} contraction twins, and {10–11}–{10–12} double twins. After twinning, high strain energy is accumulated in twin bands because their crystallographic orientations are favorable for basal slips, leading to subsequent DRX at the twin bands. Accordingly, twinning activation and twinning-induced DRX behavior play crucial roles in accommodating plastic deformation during HSR and in varying microstructure and texture of the high-speed-rolled (HSRed) sheets. Area fraction of fine DRXed grains formed at the twin bands increases with increasing rolling reduction, which is attributed to the combined effects of increased strain, strain rate, and deformation temperature and a decreased critical strain for DRX. Size, internal strain, and texture intensity of the DRXed grains are smaller than those of unDRXed grains. Therefore, as rolling reduction increases, average grain size, stored internal energy, microstructural inhomogeneity, and basal texture intensity of the HSRed sheets gradually decrease owing to an increase in the area fraction of the DRXed grains. 相似文献
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This study demonstrates that the initial texture of Mg alloy significantly affects the microstructure developed during cold rolling and the recrystallization behavior during subsequent annealing. In a sample with a texture oriented toward the normal direction(ND sample), thick and large-sized shear bands are intensively formed during cold rolling and the deformation is strongly localized along these bands. In contrast,in a sample with a texture oriented toward the transverse direction(TD sample), many {10-12} twins are formed at the early stage of cold rolling, and then, numerous small-sized shear bands are formed in these twins. Results of nanoindentation tests reveal that the cold-rolled ND sample has internal strain energy that is substantially concentrated along the shear bands, whereas the cold-rolled TD sample has a large amount of internal strain energy that is homogeneously distributed throughout the material;this latter behavior is strongly related to the extensive {10-12} twinning and the resultant microstructural variations in the TD sample. During subsequent annealing, recrystallization occurs locally along the shear bands in the ND sample, which leads to the formation of a bimodal grain structure comprising fine recrystallized grains and coarse unrecrystallized grains. In contrast, during subsequent annealing of the TD sample, static recrystallization occurs homogeneously throughout the material, which results in the formation of a uniform grain structure that mostly comprises equiaxed recrystallized grains. 相似文献
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Maoyin WangRenlong Xin Bingshu WangQing Liu 《Materials Science and Engineering: A》2011,528(6):2941-2951
Wedge-shaped AZ31 plates with two kinds of initial textures were rolled at 573 K to investigate the effect of initial texture on dynamic recrystallization (DRX). The results indicated that the initiation and nucleation of DRX were closely related to the initial texture. The initiation and completion of DRX in the TD-plate were significantly retarded compared with that in the ND-plate. Twin related DRX nucleation was mainly observed in the ND-plate samples; while gain boundary related DRX nucleation was mainly observed in the TD-plate samples. The different DRX behavior between the TD- and ND-plates was attributed to the different deformation mechanism occurring before DRX initiation. For the ND-plate, dislocation glide was considered as the main deformation mechanism accompanied with {1 0 −1 1}-{1 0 −1 2} double twin, which led to the increment of a faster increasing stored energy within the grains. And {1 0 −1 1}-{1 0 −1 2} double twin was mainly found to be DRX nucleation site for the ND-plate. For the TD-plate, {1 0 −1 2} extension twin was the dominant deformation mechanism which resulted in a basal texture with the c-axis nearly parallel to ND. The stored energy caused by dislocation motion was relatively small in the TD-plate before a basal texture was formed, which was considered as the main reason of that DRX was retarded in the TD-plate compared with that in the ND-plate. Based on the difference in deformation mechanism and DRX mechanism caused by the different initial texture, the variation in grain size, micro-texture and misorientation angle distribution in the ND and TD plates were discussed. 相似文献
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Cube texture is a sharp recrystallization texture component infcc metals like aluminium, copper, etc. It is described by an ideal orientation i.e. (100) (100). The subject of cube texture
nucleation i.e. cube grain nucleation, from the deformed state of aluminium and copper is of scientific curiosity with concurrent
technological implications. There are essentially two models currently in dispute over the mechanism of cube grain nucleation
i.e. the differential stored energy model founded on the hypothesis proposed by Ridha and Hutchinson and the micro-growth
selection model of Dugganet al. In this paper, calculations are made on the proposal of Ridha and Hutchinson model and the results are obtained in favour
of the differential stored energy model. It is also shown that there is no need for the micro-growth model. 相似文献
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A new procedure consisting of the cross shear rolling (CSR) and the subsequent tertiary recrystallization annealing under dry hydrogen atmosphere was developed to produce the grain oriented ultra-thin silicon sheets less than 0.1 mm with high magnetic property performance. For comparison, the conventional rolling (CR) was also used to process the grain oriented ultra-thin silicon steel sheets. The effect of processing parameters on magnetic properties of the grain oriented ultra-thin silicon steel sheets was investigated. With the increase of annealing temperature and holding time, magnetic properties of the sheets processed by both rolling methods reach saturation as the result of the proceeding of the tertiary recrystallization. The thin sheets rolled by CSR did achieve better magnetic properties than those rolled by CR. 相似文献
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Bettina Lommel Willi HartmannAnnett Huebner Birgit KindlerJutta Steiner 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,655(1):44-46
The investigation of the distribution of the fusion-barrier height by heavy-ion collisions requires thin self-supporting targets. To increase the accuracy of the measurement the thickness and homogeneity has to be known as precisely as possible.We prepared the self-supporting nickel foils out of the isotopes 58Ni, 60Ni and 61Ni. The resulting targets were between 75 and 105 μg/cm² thick. The foils were produced on copper backing by electron-beam gun evaporation and by extracted ion-beam sputtering, both in high vacuum. To obtain self-supporting nickel foils the copper was removed by etching. We will discuss and compare both methods. 相似文献
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A macro- and micro-combined model has been developed to simulate the static and dynamic recrystallizations of austenite during hot rolling of steel. In addition to the coupled thermal and mechanical phenomena, a micro-constitutive relationship is used to link the macro and micro models. The macro model provides the thermal and deformation information for the micro model. A finishing line with seven stands is studied to verify the model's reliability. The results indicate that static recrystallization plays a more important role than the dynamic part in austenite refinement. 相似文献
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The present work describes the preparation of near-full density Cu–Al–Ni shape memory alloy (SMA) strips via a novel processing route consisting of ‘spray deposition’ of atomised liquid Cu–Al–Ni alloy with a jet of argon gas followed by hot-rolling densification of the deposited preform. The subsequent homogenisation of the hot rolled Cu–Al–Ni strips resulted in complete martensitic structure in the finished strip, consisting of self-accommodated plates of β1′ and γ1′ martensites. The characteristic transformation temperatures and shape memory effects of Cu–Al–Ni strips were studied. It has been demonstrated that the Cu–Al–Ni SMA strips, prepared in the present work, resulted in relatively finer grain size with better combination of strength and ductility compared to other techniques based on conventional casting method. 相似文献