双辊薄带连铸1.7%Si无取向硅钢组织与织构北大核心CSCD

采用双辊薄带连铸工艺试制了1.7%Si无取向硅钢铸带,并采用光学显微镜及电子背散射衍射(EBSD)技术研究了其在铸轧及随后的冷轧和退火过程中的组织和织构演变特征。结果表明:铸带表层至中间层为粗大的等轴晶粒,中心层为细小的等轴晶。铸带织构为强的<100>∥ND织构,铸带冷轧后的冷轧组织中存在大量剪切带,冷轧织构由强的<110>//RD和较弱的<111>//ND织构组成。冷轧板经900℃退火后出现强的{001}<130>再结晶织构,再结晶织构的形成可以解释为择优形核和晶粒的择优长大机制。     

冷变形N18合金再结晶过程中的织构演变

采用电子背散射衍射技术(EBSD),对30%冷轧变形量的N18锆合金在530 ℃再结晶退火过程中轧面(RD-TD)和切面(RD-ND)的显微组织和织构进行了表征和分析。对于轧面,初始晶粒取向是<0001>//ND,再结晶晶粒取向主要是<0001>//ND和<1210>//RD;对于切面,初始晶粒取向主要是<1010>//RD和<1210>//RD,再结晶退火后形成<1010>//ND和<1210>//ND,以及<0001>方向分布在TD极点±85°三种不同取向的晶粒;轧面上的晶粒尺寸大于切面上的晶粒尺寸,为锆合金的再加工提供了理论支撑。     

退火温度对冷轧商业纯钛板材组织和力学性能的影响（英文）

传统的商业纯钛(CP-Ti)合金强度往往不能满足结构材料的需求。为了提高其力学性能,对冷轧CP-Ti合金在不同温度下退火,并详细研究其再结晶行为和织构演变。结果表明,部分再结晶形成的双态结构(等轴和拉长的晶粒)表现出极限抗拉强度(702MPa)和总伸长率(36.4%)的优异结合。CP-Ti板材的再结晶形核优先发生在高应变和大角度晶界区域。同时,变形不均匀晶粒的内部取向差增大并转变成大角度晶界,进一步促进再结晶形核。主要再结晶织构是由冷轧基面RD-分裂织构转变而来的基面TD-分裂织构,再结晶过程中定向形核起主导作用。     

冷轧Mg-Zn-Ca镁合金板材的织构演变和力学性能

系统地研究了弱织构的Mg-Zn-Ca合金板材在交叉冷轧和后续单向冷轧过程中的织构演变及力学性能。结果表明:合金板材交叉冷轧后的退火织构呈椭圆形分布。后续单向冷轧退火后的织构演变成环形分布的均匀织构。退火初期形成的再结晶晶粒与最终的完全再结晶晶粒的取向分布几乎是一致的。再结晶晶核的取向相对于变形母体晶粒具有较大的分散性,这造成退火织构的均匀随机分布,从而减小板材的面内各向异性。     

铁硅合金轧制-退火过程中立方取向晶粒的形核与长大

利用金相显微镜和EBSD技术分析研究了Fe-3.2%Si合金二次冷轧织构、(100)[001]立方取向晶粒形核、初次再结晶以及二次再结晶后立方织构的形成。结果表明,二次冷轧之后的织构主要为{111}<112>和{111}<011>,并存在少量的{112}<110>,同时在变形晶粒内部存在有接近{100}<001>取向的微区。冷变形晶粒内部各微区取向连续变化,并且逐渐向近立方取向靠近。冷变形晶粒内部立方取向的微区作为形核的核心,在退火过程中利用(100)晶粒低表面能和γ→α相变最终发展成为具有集中立方织构的柱状晶组织。     

IF钢退火过程中再结晶行为的EBSD表征

借助EBSD等技术研究了从冷轧到退火过程中IF钢中铁素体再结晶晶粒的取向演变。研究结果表明,从冷轧到退火过程中,铁素体晶粒取向向着平行于法向的[111]晶粒演变,而平行于法向的[100]晶粒逐渐消失;在冷轧变形过程中,铁素体晶粒的晶体取向决定着发生滑移变形的难易程度,与[100]晶粒相比,[111]晶粒更易于发生滑移变形,并在晶粒内部积累大量的位错,储存了大量的应变能,在随后的退火过程中,应变能较高的[111]晶粒优先形核并长大,优先发生再结晶,而应变能较低的[100]晶粒的再结晶受到阻碍。随着退火温度的升高,γ织构([111]//ND)明显增强,其织构组分(111)[112]尤为明显。     

二次退火对TA1冷轧板织构及各向异性的影响

摘要:研究了二次退火TA1冷轧板的织构以及力学性能各向异性。采用电子背散射衍射对晶粒织构和取向进行了表征,通过对轧制面进行不同加载方向的单向拉伸试验检测了力学性能。结果表明,经过一次退火后,织构的取向强度降低,<0001>//ND织构消失,■//RD向■//RD偏离60°附近产生较强的棱锥型织构,板面各向异性显著增强。二次退火后,晶粒进一步趋向于等轴化,织构类型和一次退火相比没有变化,增强了由再结晶产生的■//RD织构的强度,但进一步减小了整体织构强度,板面各向异性明显降低。一次退火后,由于对称性<0001>//ND基面织构的消失以及非对称棱锥型织构的产生,导致板面的力学性能各向异性较强。经过二次退火处理后,在织构类型不变的情况下织构强度减弱,各向异性有所改善,提高了板材的成形性能。     

冷轧Zr-1Sn-0.3Nb-0.3Fe-0.1Cr合金在退火过程中的组织演变及再结晶行为（英文）

通过硬度测试、SEM、TEM及EBSD研究变形量、退火温度及时间对冷轧Zr-1Sn-0.3Nb-0.3Fe-0.1Cr合金再结晶行为及动力学的影响。结果表明,该合金的再结晶速率随着退火温度的升高及冷轧变形量的增加而加快。退火过程中再结晶晶粒在位错缠结的高储能处优先形核长大。板材织构由?1010?//RD的基面织构转变为?1120?//RD的基面织构。再结晶晶粒形成较多的30°取向差。同时,通过JMAK方程拟合出合金再结晶动力学参数及30%、50%和70%变形量条件下的再结晶图,获得其再结晶激活能分别为240、249和180 k J/mol。     

热轧组织对冷轧无取向硅钢退火织构及组织的影响

对不同加热温度处理的热轧低硅钢带进行了冷轧及退火实验,分析了热轧钢带的组织对冷轧无取向硅钢再结晶退火过程中的组织及织构的影响。结果表明:热轧组织对冷轧无取向电工钢冷轧板再结晶组织及织构演变有重要影响;等轴晶粒组织的热轧钢带比混晶组织的热轧钢带冷轧后再结晶退火快,且退火后晶粒尺寸均匀;随着等轴晶粒尺寸增加,冷轧退火后形成的冷轧硅钢{110}类型的织构增强,{100}类型的织构减弱;表明热轧组织为等轴晶粒时,不利于冷轧无取向硅钢磁性能的改善。     

工艺参数对冷轧无取向硅钢再结晶织构的影响

分析了硅含量为2.0 wt%的高牌号冷轧无取向硅钢冷轧变形量和不同退火温度对再结晶织构及晶粒尺寸的影响。结果表明,热轧板表面与心部组织和织构的差异对后续冷轧和再结晶退火的织构和晶粒尺寸有明显影响。热轧板表面的退火态晶粒组织使其织构转变滞后于心部,并可造成最终退火后较强的{001}〈110〉织构和均匀的{111}织构,有利于磁性的改善。提高冷变形量会增加再结晶形核率而减小晶粒尺寸,提高再结晶温度不明显改变再结晶织构但增大晶粒尺寸,但应防止过高温度下析出相粒子的回溶。分析表明,热轧板常化工艺,以及二次冷轧加中间退火工艺均有利于改善钢板成品织构,进而改善钢板磁性能。     

溅射靶材用Cr20Ni80合金管材的微观组织与再结晶退火

对溅射靶材用Cr20Ni80合金冷轧管材的微观组织和再结晶退火工艺进行了研究。首先观察了冷轧管材轴向与径向的微观组织变化;其次利用JMatPro计算了Cr20Ni80合金的相图,并设计了再结晶退火工艺;最后对冷轧管材进行了再结晶退火试验,表征了退火后管材的微观组织、晶粒尺寸和硬度。结果表明,冷轧管材沿轴向均为拉长晶,且存在大量孪晶;管材沿径向的微观组织中晶粒尺寸因形变量的增大而减小;当再结晶退火温度为690 ℃时,冷轧管材试样已开始发生再结晶;790 ℃×30 min时,形变晶粒已完全再结晶,平均晶粒尺寸为24.1 μm,为最优再结晶退火工艺;当退火温度进一步升高、保温时间进一步延长时,再结晶晶粒逐渐长大;试样的硬度随退火温度的升高而减小。     

Microstructure Evolution and Hardness of an Ultra-High Strength Cu-Ni-Si Alloy During Thermo-mechanical Processing

Microstructure evolution and hardness changes of an ultra-high strength Cu-Ni-Si alloy during thermo-mechanical processing have been investigated. For hot-compressive deformation specimens, dynamic recrystallization preferentially appeared on deformation bands. As deformation temperature increased from 750 to 900 °C, elongated grains with the Cubic texture {001} 〈100〉 were substituted by recrystallized grains with Copper texture {112} 〈111〉. For the samples having undergone cold rolling followed by annealing, static recrystallization preferentially occurred in the deformation bands, and then complete recrystallization occurred. Goss, Cubic, and Brass textures remained after annealing at 600 and 700 °C for 1 h; R texture {111} 〈211〉 and recrystallization texture {001} 〈100〉 were formed in samples annealed at 800 and 900 °C for 1 h, respectively. For samples processed under multi-directional forging at cryogenic temperature, the hardness was increased as a result of work hardening and grain refinement strengthening. These were attributed to the formation of equiaxed sub-grain structures and a high dislocation density.     

Microstructure and texture evolution of AZ31 magnesium alloy during rolling

The production of magnesium alloy sheets normally involves several processing stages including hot rolling,cold rolling and intermediate annealing.The microstructure and texture evolution of AZ31 magnesium alloy sheets in different processing states were investigated by optical microscopy and X-ray diffraction technique.It is found that the microstructure of hot-rolled sheets is dominated by recrystallized equiaxed grains,while that of cold-rolled sheets is dominated by deformation twins.With final annea...     

Deformation of cube-oriented grains and formation of recrystallized cube grains in a hot deformed commercial AlMgMn aluminium alloy

The cube orientation is usually found to be the strongest recrystallization texture component in annealed aluminium. The purpose of the present work was to obtain a better understanding of the cube orientation, both with respect to the behaviour of cube-oriented grains during deformation and the formation of recrystallized cube grains. Extensive use was made of the EBSP technique to characterize samples of a hot deformed AlMgMn alloy and plane strain compression tests were used to simulate hot rolling under a wide range of conditions of strain, strain rate and temperature. The investigations included: (i) the stability of cube-oriented grains during deformation, (ii) characterization of cube-oriented regions in the as-deformed state and (iii) nucleation of recrystallized cube grains. The work has demonstrated that cube-oriented grains present in the material prior to deformation remain orientation metastable during deformation and are deformed to bands. These cube bands have a unique subgrain size distribution with a long tail of large subgrains, making them very potent as nucleation sites for recrystallized grains. Nucleation of recrystallized cube grains takes place preferentially from those bands which are surrounded by the S deformation texture component.     

Relating Initial Texture to Deformation Behavior During Cold Rolling and Static Recrystallization Upon Subsequent Annealing of an Extruded WE43 Alloy

Deformation behaviors during cold rolling and static recrystallization behaviors upon subsequent annealing of an extruded WE43 alloys with different initial textures were investigated in this study. Three types of differently textured WE43 initial alloys were labeled as samples Ⅰ, Ⅱ and Ⅲ. The results showed that multiple twinning modes and basal slip dominated the deformation of samples during cold rolling. Cold-rolled sample Ⅰ activated the larger number of double twins with high strain energy...     

Influence of deformation twinning on static annealing of AZ31 Mg alloy

The microstructure evolution during isothermal static annealing of magnesium alloy AZ31 was investigated to critically evaluate the contribution of extension and contraction twins to the recrystallized microstructure after room temperature deformation, and to establish the potential of these twins to alter the recrystallized texture. Contraction twins were observed to be potent sites for recrystallized nuclei having many favorable new orientations, while extension twins were not effective nucleation sites for recrystallization. Although recrystallization nucleated preferentially inside the contraction twins, producing a distribution of new orientations (far from the undesirable starting c-axis fiber texture), these new grains did not significantly influence the final texture. This was attributed to four factors: (1) unusually extensive recovery before the onset of recrystallization after c-axis compression in most grains; (2) incomplete recrystallization within grains most closely aligned with the starting fiber texture; (3) sluggish growth of grains nucleated in the compression twins; (4) grain boundaries becoming an active site for recrystallized nuclei with a majority containing orientations from the starting texture.     

Microstructure and texture evolution of the cold-rolled AZ91 magnesium alloy strip under electropulsing treatment

The effect of electropulsing treatment (EPT) on the microstructure and texture evolution of the cold-rolled AZ91 magnesium alloy strip was investigated using X-ray diffraction (XRD) and electron backscattered diffraction patterns (EBSD). The results indicated that EPT accelerated tremendously the recrystallization behaviour of the cold-rolled AZ91 magnesium alloy strip at a relatively low temperature within a short time of 7 s. It also suppressed precipitation of β-Mg₁₇Al₁₂ phase, compared with conventional heat treatment. The recrystallized grains favourably weakened the intensity of the basal texture. A mechanism for rapid recrystallization process during EPT was proposed based on the enhancement of nucleation rate and atomic diffusion resulting from the coupling of the themal and athermal effects.     

退火对冷轧Al0.2CoCrFe2Ni高熵合金组织和力学性能的影响

研究了不同温度退火对80%冷轧Al_0.2CoCrFe₂Ni高熵合金显微组织和力学性能的影响。使用X射线衍射仪(XRD) 、电子背散射衍射仪(EBSD)、微控电子万能试验机分别对合金进行了晶体结构、织构类型和力学性能的表征。结果表明,合金在铸态、轧制态以及退火态都表现为稳定FCC晶体结构。合金铸态下呈现典型的树枝晶组织,经80% 轧制后出现了明显的轧制变形带,在随后的退火过程中发生再结晶,其再结晶晶粒体积分数及其晶粒尺寸随着退火温度的升高而增加。合金经过80%轧制后主要表现为(111)<112>织构,其织构强度随着退火温度的升高而降低。80%轧制使Al_0.2CoCrFe₂Ni合金获得较大的抗拉强度(1005 MPa)和较低的塑性(10%), 随着退火温度的提高,合金的强度降低塑性增强,并在700 ℃退火时合金获得最佳的综合力学性能,该过程主要取决于合金中的位错密度、再结晶体积分数和晶粒尺寸及其再结晶织构的演变。