时效工艺对6061铝合金力学性能各向异性的影响及微观组织研究

Effect of Aging Processes on the Anisotropic Mechanical Property of 6061 Aluminum Alloy and the Related Microstructure Evolution

采用单向拉伸试验研究了经不同时效工艺处理的6061铝合金轧制板材在轧制方向(0°)、倾斜方向(45°)和横向(90°)的力学性能各向异性。实验结果表明,轧制态6061铝合金的力学性能与热处理工艺密切相关,且表现出明显的各向异性。其中T6态6061铝合金力学性能各向异性最不明显。轧制态6061⁃T6铝合金有较强的立方织构{001}〈100〉和较弱的织构成分{001}〈100〉,目前采用的人工时效方法对其晶粒的显微组织和织构演化的影响不大。相对于经其他工艺处理的轧制态6061铝合金,经240℃高温时效处理的轧制态6061⁃T6铝合金位错密度大,且分布更均匀。轧制态6061⁃T6铝合金中明显的高密度β″析出物是其具备最高强度和最低各向异性的主要原因。

The effect of aging on the anisotropic mechanical properties of a commercial 6061 rolling sheet has been investigated by 0°,45°and 90°uniaxial tensile tests.The mechanical properties of the studied alloy are strongly related to the applied heat treatment state and loading direction,exhibiting visible anisotropy.The T6 treated alloy exhibits the lowest anisotropy as compared with the other treated alloys.In addition,the studied alloys has a strong cube{001}〈100〉and a much weaker{001}〈100〉components.The artificial aging utilized in present work has little influence on the grain microstructure and texture evolution.The dislocation distributions of T6 and HTA 240℃alloys are denser and more homogeneous as compared with those in other treated alloys,and the visibly higher density ofβ″precipitates in T6 alloy is the main reason for the highest strength and the lowest anisotropy.