摘要
In order to investigate the dependence of microstructure and mechanical properties on the rolling process parameters, AZ31 magnesium alloy sheets with different grain sizes, basal texture intensities and twinning types were obtained using hot rolling at various temperatures and reductions. The volume fractions of the extension, contraction and secondary twins in the as-rolled sheets depend on the grain size. The highest volume fractions of three types of twins are obtained at 523 K under the reduction of 10% when the average grain size value is the maximum. The critical reductions for complete dynamic recrystallization are 30% at 523 K and 40% at 473 K. The increase of yield strength is ascribed to both grain-refinement strengthening and basal texture strengthening at the first stage. When the grain size does not decrease with increasing the reduction, the yield strength is mainly influenced by the texture weakening.
为了考察轧制工艺参数对板材显微组织和力学性能的影响,通过不同温度和轧制变形量的热轧工艺得到具有不同晶粒尺寸、基面织构强度和孪晶类型的AZ31镁合金轧制板材。拉伸孪晶、压缩孪晶和双孪晶的体积分数与AZ31镁合金轧制板材的晶粒尺寸有关。当轧制温度为523 K、轧制变形量为10%时轧制得到的板材,三种类型孪晶的体积分数最高,此时晶粒尺寸最大。在轧制温度分别为523和473 K时,板材发生完全动态再结晶的临界变形量分别为30%和40%。拉伸实验结果表明:随着轧制变形量的增加,在第一阶段,轧制后板材屈服强度的提高主要依赖于晶粒细化强化和织构强化;当晶粒尺寸随变形量的增加不再发生明显的细化时,板材的屈服强度主要受织构弱化的影响。
