不同热处理工艺对7003铝合金组织和性能的影响

Effect of Different Heat Treatment Processes on Microstructure and Properties of 7003 Aluminum Alloy

通过硬度、拉伸强度、导电率、应力腐蚀测试和电子显微镜观察,研究了峰值时效T6、双级时效T73和回归再时效RRA三种热处理工艺对7003铝合金力学性能和抗应力腐蚀性能的影响。结果表明:在T6状态下,铝合金的强度最高为440 MPa,但抗应力腐蚀性能较差,导电率为39.1%IACS;经过T73处理后,合金的抗应力腐蚀性能得到提高,导电率达41.1%IACS,但强度下降到375 MPa;而回归再时效(RRA)热处理既能使合金接近T6态的强度,又能显著提高合金的抗应力腐蚀性能。RRA热处理的铝合金,其晶界析出相粗大且断续分布,是合金具有较好抗应力腐蚀性能的重要原因之一。

Through hardness, tensile strength, electrical conductivity, stress corrosion test and electron microscope observation, the effects of three kinds of heat treatment technology （peak aging T6, double aging T73 and regression again aging RRA） on mechanical properties and stress corrosion resistance of 7003 aluminum alloy were studied. The results show that in the T6 state, the strength of the aluminum alloy is the highest （440 MPa）, but the stress corrosion resistance is poorer, and the conductivity is 39.1% IACS; after T73 treatment, the corrosion resistance of the alloy improves, the conductivity reaches 41.1%IACS, but the strength decreases to 375 MPa; and the regression again （RRA） heat treatment can not only make the alloy close to the strength of the T6 state, but also can significantly improve the corrosion resistance of the alloy. For aluminum alloy of RRA heat treatment, the grain boundary precipitates is coarse and in intermittent distribution, which is one of the important reasons for good stress corrosion resistance of the alloy.