对高锰相变诱发塑性(TRIP)钢冷轧过程的组织转变特征以及奥氏体(γ )和bcc结构马氏体(α'-M)的织构演变规律进行了研究,对形变诱发α'-M在高温时的逆转变行为进行了分析。结果表明,中等变形量下γ 已经大部分转变为α'-M,此时残余的γ 和hcp结构马氏体(ε -M)接近机械稳定化。变形量进一步增加时,主要发生α'-M的形变并形成平行于轧向(RD)的长条状组织。中等变形量下,α'-M主要具有{113}<110>、{554}<225>和旋转立方({001}<110>)等典型的相变织构。随变形量增加,α'-M的{113}<110>取向明显转向稳定取向{223}<110>,形成典型的冷轧织构(<110>∥RD)。在650~850 ℃退火时发生了α'-M的逆转变(α'-M→γ )及γ 的再结晶。α'-M的逆转变以扩散方式进行,存在Mn、Al元素在γ 和α'-M中的再分配。α'-M的逆转变是通过γ 直接吞并临近的形变α'-M完成的,形成的γ 晶粒为长条状且存在较多的亚晶。逆转变形成的γ 与形变γ 的织构类型相同,这种织构遗传是由于残余γ 直接长大产生的。随退火时间延长,长条状γ 晶粒又通过亚晶合并的方式发生再结晶而被等轴γ 晶粒取代。

To meet the requirement of environment, economy and safety, advanced high strength steels including dual phased (DP), complex phased (CP), transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) steels are widely used for automotive steel. Among them, high manganese TWIP and TRIP steels are particularly appealing due to their outstanding tensile strength and elongation. In contrast to high manganese TWIP steel, high manganese TRIP steel exhibits higher strength and work hardening rate due to strain induced martensitic transformation. The enhanced mechanical properties of high manganese TRIP steel are determined by both the stability of the retained austenite (γ ) and the initial microstructure. Strain induced martensitic transformation and subsequent reversion from deformed martensite to γ during annealing is often applied as one of the most effective methods for microstructure improvement. Microstructure and texture characteristics of high manganese TRIP steel during cold rolling together with the reversion of deformed bcc martensite (α'-M) at high temperature were investigated. It is shown that the γ was almost completely transformed into α'-M at medium cold rolling reduction. And a higher reduction after α'-M saturation resulted in dominantly the deformation of α'-M, hence thin laths paralleled to the rolling direction (RD) were obtained. The main components in α'-M were {113}<110>, {554}<225> and rotated cube ({001}<110>) textures at medium cold rolling reduction, which are the typical phase transformation textures. The {113}<110> texture rotated toward a more stable orientation {223}<110> and led to a strong cold rolling texture (<110>//RD) with increasing reduction. The reversion of martensite and recrystallization of γ proceeded at temperature ranging from 650 ℃ to 850 ℃. The reversion of α'-M proceeded in a diffusional mechanism, accompanying with the redistribution of Mn and Al between γ and α'-M. Deformed α'-M was merged by the adjacent γ , and columnar γ grains with a large amount of subgrains were obtained. The texture of reverted γ was approximately the same as that of the deformed γ , this phenomenon called texture inheritance was formed by the direct growth of γ . Subsequently, recrystallization of γ grains occurred by sub-grain coalescence and the columnar γ grains were instead by equiaxed γ grains.