CGO硅钢初次再结晶组织及织构演变规律

对3%(质量分数)Si CGO硅钢冷轧板进行初次再结晶退火实验,设置不同的退火保温时间,将退火后的样品分别使用OM,TEM及EBSD进行分析,观察其微观组织、位错及织构分布,研究CGO硅钢初次再结晶过程中组织及织构的演变规律。结果表明:随着退火保温时间的延长,回复再结晶的程度增加,当保温时间延长至300s时,再结晶基本完成且呈现等轴晶状态,随着保温时间的延长,组织中位错密度降低。初次再结晶退火保温时间对初次再结晶织构分布有影响:随着保温时间的延长,{111}〈112〉和{110}〈112〉织构含量不断下降,{111}〈110〉织构的含量先减少后增加,立方及旋转立方组分基本保持不变,Goss织构组分逐渐增多。当保温时间较短时,晶粒取向差主要为小角度晶界并存在大量亚晶,随着保温时间的延长,大角度晶界逐渐增多。     

冷轧无取向硅钢再结晶退火组织和织构演变研究进展

总结了近年来冷轧无取向硅钢再结晶组织和织构演变的研究进展,重点总结了快速加热条件下再结晶组织和织构的研究进展.快速加热抑制回复,使再结晶发生前的剩余形变储能增加,导致形核驱动力增加并促进大角晶界迁移,因而使形核率增加、晶粒细化.同时,快速加热降低了晶核择优位向,最终降低了<111>//ND再结晶织构组分强度.     

冷轧形变量对钛板材再结晶织构形成的影响

采用三维晶体学取向分布函数（ＣＯＤＦ）分析法研究了工业纯钛板材不同冷轧形变量对织构形成的影响。结果表明，冷轧形变量为５０－７０％时，再结晶退火后形成了（２１１８）（０１１０）和（１０１８）（１２１０）的部分纤维织构，而在３０％较低或８６％较高的形变量冷轧时，形成典型的轧制织构（２１１５）（０１１０）和再结晶织构（１０１３）（１２１０）型式。     

冷轧Al_(0.3)CoCrFeNi高熵合金退火再结晶组织和织构的演变

利用维氏硬度计(HV)、X射线衍射仪(XRD)、电子背散射衍射(EBSD)和透射电镜(TEM),研究了90%冷轧Al0.3CoCrFeNi高熵合金在900℃退火过程中的微观组织和织构演变规律。结果表明:退火0.5h合金发生完全再结晶,退火孪晶形成于再结晶面心立方(FCC)晶粒内;经退火1h后,富集Al-Ni原子的有序体心立方(BCC)相优先于FCC相的晶界处形核,且FCC相和BCC相均随着退火时间(1h~10h)的延长而发生晶粒长大。再结晶FCC相的织构组分主要为强{123},〈634〉S织构和强α-{110}纤维织构,{001}〈100〉立方织构随着退火时间的延长也逐渐转化为强织构;再结晶过程的进行使无择优取向的初始BCC晶核选择性长大,{111}〈112〉织构从而演变为强BCC相织构。     

高纯铜冷轧形变组织及织构演变规律研究

采用纯度99.99%的高纯铜进行30%、50%、70%、90%形变量冷轧加工,对不同形变量下高纯铜的晶粒尺寸、分布等微观组织及织构进行了定量研究。结果发现,随着形变量的增加,平均晶粒尺寸、晶粒尺寸方差不断减小,晶粒高宽比(形状因子)逐渐增加,晶粒逐渐转变为纤维状;冷轧织构(Brass、S、Copper)含量逐渐增加,其中Brass织构最多,S织构次之,Copper织构最少。形变量至90%后,冷轧织构含量增至85%以上,晶粒逐渐向标准极射三角形中间部位聚集,在{101}方向有显著聚集,{111}方向始终无明显聚集。α取向线及β取向线上织构含量逐渐增加,均出现明显的集中织构,形变量从70%增加至90%时织构的增加最明显。     

钽材轧制和再结晶织构演变研究进展

钽作为一种稀有难熔金属,耐化学腐蚀、电子迁移率低、延展性好、价格昂贵,常用在具有特殊性能要求的苛刻环境中。近些年来,钽材的生产工艺逐步改进,性能不断提高,但生产过程中其晶粒不可避免地会出现择优取向,即织构。织构能明显影响钽材的性能,不同用途的钽制品对织构的要求也不同,深冲时要求有强烈的{111}织构,溅射时需要织构均匀分布。轧制工艺和再结晶退火作为改变晶体材料各向异性的主要手段,前者可影响滑移系的激活和晶粒的转动状态,形成不同的轧制织构,后者能使特定取向的晶粒优先形核并快速长大,形成再结晶织构。国内外对金属材料的织构进行了大量研究,然而主要集中于钢铁和面心立方晶粒材料,对于钽这样的稀贵金属的织构研究较少。主要综述了钽材在轧制和再结晶过程中织构的变化规律,重点介绍了钽材冷轧和再结晶织构演变的研究现状及最新进展。     

对高温超导Ag基带再结晶织构的研究

通过对变形量为94.8%的Ag带在110℃不同时间下再结晶退火,并对其ODF和△ODF分析发现,Ag的再结晶是一个定向形核和长大的过程,再结晶时晶面基本保持不变,在晶面内晶向发生转动,分析可知在{023}面内{023}<301>取向首先转变为{023}<123>取向然后再转变成{023}<110>取向,在{110}面内,高斯、黄铜取向及{110}<311>取向不断减弱转变为{110}<110>取向,所以控制冷轧取向集中在{110}面上,可以获得取向更为集中的{110}<110>取向.     

再结晶织构的计算模拟理论及意义

阐述了再结晶织构模拟的研究的意义，介绍了目前流行的再结晶织构及晶粒生长的模拟理论－蒙特卡洛方法以及国内模拟研究的新进展。     

冷轧纯铜微观组织及织构演变的特征

介绍了电子背散射技术（EBSD）在材料织构方面的研究应用状况,并采用EBSD研究了纯铜在冷轧过程中晶粒的变化、晶粒取向及晶界角度分布的特征。结果表明,纯铜在经过大变形量后出现轧制织构,其轧制织构主要是{112}〈111〉和{011}〈112〉织构;在中小变形量下,随着变形量的增加大角度晶界逐渐减少,而到高变形量时逐渐增加。     

退火时间对单向异步轧制70—30黄铜再结晶织构的影响

借助三维取向分布函数探讨了退火时间对单向异步轧制７０－３０黄铜再结晶结构及其宏观统计不对称性的影响，结果表明，各层再结晶织构存在明显的宏观统计不对称性，是由形变织构的不对称所致；随着退火时间的不断延长，宏观统计不对称性逐渐增强，待再结晶结束后趋于稳定。     

Analysis of Micro-texture during Secondary Recrystallization in a Hi-B Electrical Steel

The understanding of Goss texture in Hi-B electrical steels possesses significant industrial and academic value, thus attracts worldwide attention. The prevailing models for sharp Goss texture formation during secondary recrystallization are CSL (coincident site lattice) boundary theory and HE (high energy) boundary theory. These theories stress the key factor of preferred growth and the difference between them only lies in the specific selection manner. This work examined the texture gradient in primarily recrystallized sheet and demonstrated its possible influence on the formation of secondary grains, and then determined the micro- texture during different stages of secondary recrystallization using EBSD (electron back-scattered diffraction) technique, finally analyzed a special type of secondary grains with near Brass orientation, which were detected in the later stage of secondary recrystallization, and discussed its origin and effect in terms of surface energy effect. The results indicate that texture gradient in primarily recrystallized sheet will lead to a multi-stage formation of Goss texture, namely, early stage of secondary grains with various orientations in subsurface region, intermediate stage of preferred growth of Goss grains into center layer and re-grow back to the surface and the final stage of Goss grain growth by swallowing slowly the island grains with the help of H2 atmosphere.     

Effects of Primary Annealing Condition on Recrystallization Texture in a Grain Oriented Silicon Steel

The recrystallization texture in grain oriented silicon steel sheets, which were annealed at different primary annealingtemperatures with and without an electric field, was investigated. An automated electron backscattered diffraction(EBSD) technique was used to analyze the recrystallization texture. It was found that recovery and application ofelectric field in primary annealing lead to an increase of {001} component and a decrease of {111} component afterannealing at 900℃. The development of recrystallization texture can be explained in terms of the effects of electricfield and primary annealing temperature on recovery.     

Effects of External Electric Field on AlN Precipitation and Recrystallization Texture of Deep-drawing 08Al Killed Steel Sheet

The effects of an electric field on AIN precipitation and recrystallization texture were investigated. Cold-rolled 08Al killed steel sheets were annealed at 550℃ according to the two-step processes, for various maintaining times, with and without applying an electric field. It was found that the electric field promotes the precipitation of the second phase （AlN particles）, strengthens the γ-fiber and weakens the α-fiber texture component in the recrystallized specimens. A possible explanation for the reinforcement of γ-fiber texture by the electric field is that the second phase AIN particle promotes the growth of γ-fiber at the expense of differently oriented grains.     

Texture control by {10-12} twinning to improve the formability of Mg alloys: A review

Texture control of wrought Mg alloys, particularly in rolled Mg alloy sheets, has been an important research topic for the past several decades because it has significant influence on stretch formability at room temperature. For Mg alloys, {10-12} twinning can be easily activated and causes a ˜86.3° lattice rotation. Thus, pre-twinning deformation is considered as an effective and low-cost method for texture control in wrought Mg and its alloys. Furthermore, it has been verified that texture control via pre-twinning deformation can remarkably improve stretch formability of rolled Mg alloy sheets. In this review, recent researches on texture control via twinning deformation and its influence on stretch formability will be critically reviewed. The main contents include the micro-mechanism and impact factors of control in twin-orientation, plastic processing techniques of pre-inducing twins and the application of pre-induced twins in improvement of stretch formability. Finally, further research directions on this field were proposed.     

Effects of External Electric Field on AlN Precipitation and Recrystallization Texture of Deep-drawing 08A1 Killed Steel Sheet

The effects of an electric field on AIN precipitation and recrystallization texture were investigated. Cold-rolled 08Al killed steel sheets were annealed at 550℃according to the two-step processes, for various maintaining times, with and without applying an electric field. It was found that the electric field promotes the precipitation of the second phase (AIN particles), strengthens theγ-fiber and weakens theα-fiber texture component in the recrystallized specimens. A possible explanation for the reinforcement ofγ-fiber texture by the electric field is that the second phase AIN particle promotes the growth ofγ-fiber at the expense of differently oriented grains.     

Coupled simulations of texture evolution during deformation and recrystallization of fcc and bcc metals

Thermo-mechanical processing to produce optimum grain structure and texture is essential for the successful utilization of commercial aluminum alloys and steels as sheet products. Several modeling techniques have been developed in the past with a reasonably good predictive capability for bulk deformation textures. However, prediction of texture evolution during recrystallization remains very challenging because of uncertainties involved in predicting the mechanisms that lead to nuclei formation and crystallographic orientations of the nuclei, and the uncertainties involved in predicting the grain boundary properties that determine the growth kinetics of the nuclei. We present some of our recent work in modeling the recrystallization textures following cold deformation in polycrystalline bcc metals and hot-deformation in fcc metals.