ABSTRACT

The present work has examined the influence of strain path change on the deformation behaviour, texture evolution and recrystallisation process in an extruded pure magnesium. The samples were compressed at room temperature along ED, ND and ND–ED directions to the same total strain. Electron back-scattered diffraction (EBSD), hardness testing and X-ray diffraction were utilised to examine the deformed and annealed samples at different conditions. The texture evolution in the ND–ED samples showed a more significant difference than the samples monotonically deformed along ED and ND directions. As-deformed microstructures illustrate the presence of lenticular shaped twins in the ND–ED samples, while the complete flipping of original grains owing to twinning was observed in the ED and ND samples. The recrystallisation of ED deformed sample showed the fastest kinetics followed by the ND–ED and ND samples, respectively. This was rationalised based on the variation in deformation mechanisms. For all the three conditions, the formation of new grains at prior grain boundaries appeared to be the prevalent mechanism for recrystallisation. Additionally, for the ND–ED deformed samples, evidence of recrystallisation within $\{10\overline{1}2\}$ twin was reported.

摘要

目前的工作已经研究了应变路径变化对挤压纯镁中变形行为，织构演变和再结晶过程的影响。在室温下，沿ED，ND和ND–ED方向将样品压缩至相同的总应变。电子背散射衍射（EBSD），硬度测试和X射线衍射被用来检查在不同条件下变形和退火的样品。与沿ED和ND方向单调变形的样品相比，ND-ED样品的纹理演变显示出更大的差异。变形后的微观结构说明ND-ED样品中存在双凸透镜状孪晶，而在ED和ND样品中观察到由于孪晶而使原始晶粒完全翻转。ED变形样品的重结晶分别显示出最快的动力学，其次是ND–ED和ND样品。基于变形机制的变化对此进行了合理化。对于所有这三个条件，在先前的晶界处形成新晶粒似乎是再结晶的普遍机理。此外，对于ND–ED变形的样品，其内部重结晶的证据$\{10\overline{\mathrm{1个}}\mathrm{2个}\}$ 据报道有双胞胎。