AZ31B镁合金挤压板材力学性能的各向异性

在AZ31B镁合金板材的板面内沿不同方向进行单向拉伸和压缩试验,研究挤压板材的力学性能。结果表明,变形AZ31B镁合金板材具有显著的各向异性和拉压非对称性。在板面内,沿挤压方向拉伸时的屈服应力明显地比沿同方向压缩和沿其他方向拉伸或压缩时的高(约2倍);沿45°斜向拉伸的屈服应力和抗拉强度较低,而延伸率最高;这种非对称性主要表现为屈服非对称和塑性流动非对称,即拉压的屈服应力不相等和拉压应力-应变曲线形状不同,压缩曲线表现出特殊的"S"型。基于晶体塑性理论,讨论了引起变形镁合金的各向异性和拉压非对称性力学性能的变形机理。

The Mechanical Properties of Extruded AZ31B Magnesium Alloy Sheets

The mechanical properties of extruded AZ31B magnesium alloy sheets were investigated by conducting tension and compression experiments along with three different directions align in the sheet plane in this paper.The results show that extruded magnesium alloy sheets show high anisotropy and strong tension-compression asymmetry.The in-plane tensile yield stress in the extrusion direction(ED) is much bigger(about 2 times) than that of compression in the same direction and tension or compression in other directions.The tensile yield and ultimate strength in the 45°direction are smaller in some extent, while the elongation is the largest.The tension-compression asymmetry include the difference in tensile and compressive initial yield stresses(yield asymmetry) and plastic flow stresses(flow asymmetry),the compressive hardening curve turns to be unusual S-shape.The deformation mechanism which causes material anisotropy and tension-compression asymmetry was discussed based on the crystal plasticity.