固溶温度对7050铝合金组织及性能的影响

Effect of Solution Temperature on Microstructures and Mechanical Properties of Aluminum Alloy 7050

采用光学显微镜(OM)、扫描电子显微镜(SEM)、力学性能测试及断裂韧性试验研究了固溶温度对7050铝合金组织和力学性能的影响。结果表明,随着固溶温度的升高,合金晶粒发生再结晶的比例逐渐增大,合金中粗大第二相粒子逐渐减少而后趋于稳定。另外,随着固溶温度升高,合金的强度以及断裂韧性先升高后降低,试样断裂时穿晶断裂的比例逐渐增大,穿晶韧窝更多、更深,韧窝中的粗大第二相明显减少。当固溶温度超过480℃后,合金断裂方式主要为沿晶断裂。

The effect of the solution temperature on the microstructures,tensile properties and fracture toughness of 7050 aluminum al?loy were investigated by means of optical microscopy(OM),scanning electron microscopy(SEM),tensile test and plane-strain fracture toughness test.The results show that the second-phase particles of alloy decrease firstly,and then tend to be stable with the increase of solution temperature.In addition,the fraction of recrystallization of grains also increases.The strength and fracture toughness of alloy increase firstly,and then decrease with the increase of solution temperature.The fraction of transgranular fracture of sample increases during fracture process.Besides,transgranular dimpled ruptures become more and deeper,with obvious decrease of coarse dimples.When solution temperature exceeds 480℃,the fracture mode of alloy is mainly intergranular fracture.