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对AZ311镁合金热轧板材在423 K进行了双向反复弯曲变形及523 K退火处理,利用OM及SEM/EBSD技术研究了该工艺过程中的组织和织构演化规律.结果表明,孪生为其主要的变形机制,随着变形道次的增加,靠近表面的晶粒中不断地累积孪生变形,并最终被高密度的孪晶分割细化;而中部组织变化不大,仅有少量孪晶产生;样品趋向于形成两边孪晶密度大、中间孪晶密度小梯度变化的双面对称组织.6道次变形的样品在523 K退火1000 s后,表层晶粒发生了完全静态再结晶,平均晶粒尺寸由46μm细化至10μm左右,在板材两边各形成了约为1/4板厚的细晶层,且该区域的组织较为稳定.此外,其室温延伸率也由19.01%提高到了24%左右,但抗拉强度变化不大,这是由于板材两边的晶粒细化和织构弱化共同作用所致.
The microstructure and texture evolution of AZ311 magnesium alloy hot-rolled sheet were studied by two-way repeated bending and 523 K annealing at 423 K and OM and SEM / EBSD techniques. The results show that the twin With the increase of deformation pass, the twin grains near the surface continue to accumulate twin deformation and are finally refined by high-density twins. In the middle part of the structure, there is little change and only a few twins are produced. The samples tended to form bilaterally symmetric structures with large twin densities on both sides and small densities of intermediate twin densities.After annealing at 523 K for 1000 s, the surface grains were completely static recrystallized and the average grain size The size is refined from 46μm to about 10μm, a fine layer of about 1/4 plate thickness is formed on both sides of the plate, and the microstructure of the region is stable. In addition, the room temperature elongation also increased from 19.01% to 24% , But little change in tensile strength, which is due to the grain refinement on both sides of the plate and weakened texture together.