7A41铝合金的力学性能和耐蚀性能

采用常温拉伸性能测试、应力腐蚀性能测试和盐雾腐蚀性能测试方法分别对双级时效态7A41铝合金的力学性能及耐蚀性能进行了测试。采用光学显微镜、扫描电镜(SEM)和透射电镜(TEM)对合金的显微组织、拉伸断口微观形貌进行了表征。结果表明,T6状态下合金的抗拉强度、屈服强度和伸长率分别为505 MPa、474 MPa和16.3%。耐应力腐蚀性能优异,应力腐蚀敏感系数为3.98%,合金的盐雾腐蚀速度为0.0914 mm/y。TEM观察分析表明,Tb态7A41铝合金晶内均匀弥散地分布着纳米级析出相,晶界上分布着大量的非连续析出相,析出相尺寸为20~50 nm,非连续析出相有效地阻碍了合金晶间腐蚀的路径,良好的组织特征保证了合金的综合性能。

Mechanical properties and corrosion resistance of 7A41 aluminium alloy

Mechanical properties and corrosion resistance of the double-stage aged 7A41 aluminium alloy were tested by the test methods of tensile properties at room temperature, stress corrosion properties and salt spray corrosion properties, respectively. Microstructure of the alloy and the microscopic morphology of tensile fracture were characterized by metallographic microscope, scanning electron microscope(SEM) and transmission electron microscope(TEM). The results show that the tensile strength, yield strength and elongation of the alloy in T6 state are 505 MPa, 474 MPa and 16.3%, respectively. The stress corrosion resistance is excellent, the stress corrosion sensitivity coefficient is 3.98%, and the salt spray corrosion rate of the alloy is 0.0914 mm/y. TEM observation and analysis show that the nano-scale precipitates are uniformly dispersed in the double-stage aged 7A41 alloy grains, and a large number of discontinuous precipitates are distributed on the grain boundaries. The size of the precipitates is 20-50 nm. The discontinuous precipitates effectively hinder the path of intergranular corrosion of the alloy and the good microstructure characteristics ensure the comprehensive properties of the alloy.