EFFECT OF ORIGINAL ORIENTATION ON MICROTEXTURE EVOLUTION OF AZ31 Mg ALLOY
初始取向对AZ31镁合金微观织构演化的影响

The deformation behavior of AZ31 Mg alloy was studied in the temperature range from 523 to 723 K under a strain rate of 3×10-3 s-1. Cuboid samples with different orientations were machined from an extruded rod along angles of 0o, 45o and 90o to the extrusion direction, respectively. The effects of original orientation on microtexture evolution were analysed by OM and SEM/EBSD techniques. The results showed that the true stress-true strain curves were sensitive to original orientation especially below 623 K. Extensive {1012} tension twins were formed at 523 K in the 0o samples and the volume fraction of twins increased rapidly to 90\% at a strain of ε=0.3. Namely, the basal planes initially parallel to the compression axis rotated quickly by twinning to an orientation perpendicular to the compression axis. In contrast, the volume fraction of {1012} twinning in the 45o or 90o samples was lower than 10%. The initial texture in the 90o sample scarcely changes and the relative intensity decreased with increasing strain.