热拉伸变形对AZ31B镁合金薄板显微组织的影响

利用单向热拉伸实验和金相显微镜研究了AZ31B镁合金薄板热变形过程及其动态再结晶组织变化规律。结果表明,在变形温度为160℃、应变速率为1×10-3s-1时,拉伸变形后得到的显微组织是混合组织。260℃~280℃时形成均匀分布的细小等轴晶粒,其晶粒平均尺寸为5μm左右。在变形温度为320℃~400℃、变形速率为1×10-3s-1~3.3×10-4s-1时,晶粒平均尺寸为10μm~20μm,沿晶界出现氧化现象,且氧化"黑色"斑点发生聚集。

Influence of thermal tensile deformation on microstructure of AZ31B magnesium alloy thin sheet

Thermal deformation process and dynamic recrystallization structure change rules of AZ31B magnesium alloy thin sheet were investigated by uniaxial thermal tension and metalloscope.The results showed that the mixed grain microstructure can be obtained when the uniaxial tensile test was conducted under 160℃ at 1×10-3s-1.The alloy consists of equal and refined equiaxed grains during temperature 260℃~280℃,the average grain sizes are about 5μm.The average grain sizes are about 10μm~20μm in 1×10-3s-1~3.3×10-4s-1 and deformation temperature 320℃~400℃,oxidation were appeared along the boundaries of grains and oxidation macula "Black" were massed.