多晶纯铝轧制变形晶粒局部取向的演变

EVOLUTION OF LOCAL ORIENTATIONS WITHIN INDIVIDUAL GRAINS IN ROLLED PURE POLYCRYSTALLINE ALUMINUM

本文采用SEM-EBSD检测技术研究了高纯铝多晶体内(011)[100]和(210)[001]两个相邻柱状晶粒在轧制变形前、后的微取向分布.结果表明,经65%压下量后,虽然两晶粒靠近晶界部分的转动要慢于晶内的转动,但转动趋势是一致的, 两个晶粒都显示{110}∥ND(α取向线)转动.运用Taylor晶体塑性变形理论,考虑靠近与远离晶界部分具有不同程度的附加强制剪切变形(de13≠0),模拟计算的两晶粒轧制变形时局部取向演变结果与实测微取向分布图具有较好的一致性,且考虑了附加强制剪切变形的Taylor模型预测结果优于经典FC和RC-Taylor模型.

Local orientations distributions of two neighboring grains with (011)[100] and (210)[001] orientations in high purity Al polycrystal rolled up to 65% (thickness reduction) have been investigated using the SEM-EBSD technique. It is found that the rotating angles of the zones closed to the grain boundary (boundary part, BP) are less than those of the zones far from the boundary (inner part, IP), but their rotating tendency is the same, i.e., {110} // ND (alpha-fiber), however, the rotating rate of the BP is slower than that of the IP, which reveals the rotating incompatibility and the heterogeneity of the local orientations within individual grains during rolling. It is suggested that various added prescribed shears (APS, de(13) not equal 0) should be introduced into the BP and IP, the calculated local orientation distributions in the BP and IP with the suggested APS-Taylor models, well agree with the experimental OIMs (orientation imaging micrographs), and the APS-Taylor models are much better than the classical FC-Taylor and RC-Taylor models for prediction of the evolution of local orientations in grains.