交叉预压缩对轧制态AZ31镁合金拉压不对称性的影响

Effect of Multidirectional Pre-compression on the Tension-Compression Asymmetry in a Hot-Rolled Mg-3Al-1Zn Alloy

摘要:

通过对轧制态AZ31镁合金板材进行多向预压缩，运用塑性变形的方式，产生了{102}一次拉伸孪晶和{102}-{102}二次拉伸孪晶，并结合EBSD表征和XRD分析，对预压缩后材料的拉伸压缩实验的结果表明，预压缩对镁合金拉压不对称性的降低和强度的提高有明显效果。交叉预压缩之后，由于产生了孪生，材料组织晶粒细化，使得材料在再变形时，屈服强度和最大强度均明显增强。产生的拉伸孪晶片层可以有效地改变晶粒的取向，在一定程度上削弱了基面织构，在{102}一次拉伸孪晶中产生了{102}-{102}二次拉伸孪晶，二者结合作用，改善了材料的再变形行为，从而降低了镁合金板材的拉压不对称性。

Abstract:

The effect of pre-compression on the tension-compression asymmetry in a hot-rolled Mg-3Al-1Zn alloy was investigated by Electron backscattered diffraction (EBSD) and X-ray diffraction (XRD). The tensile and compressive tests of the pre-compressed materials reveal that the tension-compression asymmetry is greatly reduced via pre-compression, which results in the production of twins facilitating the grain size refinement. Yield strength and peak strength are obviously enhanced. The orientation of the grains and the intensity of the basal texture are effectively modified through the twins resulted from pre-compression. Additionally, {102}-{102} twins are found to be generated in the previously formed {102} twins. The existence of these twins modifies the deformation behavior of the materials during re-deformation, which is beneficial to the reduction of the tension-compression asymmetry.