取初始织构为c轴与板面法向垂直的强织构AZ31镁合金板材为初始样品,经液氮温度深低温轧制多道次至不同变形量,研究所得轧制板材的显微组织与织构演变,及其对轧制力学性能的影响。利用SEM、EBSD和XRD表征分析了轧制板材的显微组织和织构,应用准静态单轴拉伸实验分别测试了深低温轧制板材沿轧向(RD)和横向(TD)的室温力学性能。研究表明,{101?2}拉伸孪晶是深低温轧制强织构AZ31镁合金板材中的主导孪晶类型,其对轧制板材的微观组织和织构影响较为显著。轧制变形后,大量的拉伸孪晶晶界不但对晶粒起到了分割碎化作用,并且由于孪晶对取向的剧烈改变,使得板材在轧制变形后c轴平行于ND的织构组分加强。深冷轧制板材的强度有所提高,但是延伸率却急剧下降,沿着RD方向的强度要高于TD方向的强度。

A strongly basal textured AZ31 magnesium alloy sheet with the normal direction (ND) perpendicular to the c-axis has been cryorolled at the liquid-nitrogen temperature to the strain of different amount to analyze the influence of cryogenic rolling temperature. The microstructure and texture of the cryorolled samples have been investigated by using SEM, EBSD and XRD. And the mechanical properties of the cryorolled sheets have also been tested under quasi-static uni-axial tension at the ambient temperature along the rolling direction (RD) and transverse direction (TD) respectively. The microstructural and textual evolutions of the strongly basal textured AZ31 magnesium alloy sheets during cryorolling and the relationship between mechanical properties and the microstructural and textural evolutions of cryorolled samples has also been discussed in this work. The results show that a lot of twins have been observed in cryorolled sheets, and they were found to be {101?2} tension twins. {101?2} tension twins were the dominant twinning type of the AZ31 magnesium alloy sheet during cryogenic rolling. With the increase of cryogenic rolling pass, new texture component with the c-axis paralleled to the normal direction (ND) was strengthened and the breadth of {101?2} tension twins was also increased. Grains were separated by the twin grain boundaries after cryorolling. The mechanical test results show that the strength of the sheets increased while the ductility decreased after cryogenic rolling. The strength of the sheets along RD was higher than that along TD.