不同时效处理对7075高强度铝合金组织性能的影响

Effects of Different Aging Treatment on Microstructure and Properties of 7075 High Strength Aluminum Alloy

对7075高强度铝合金分别进行T6单级时效、双级时效以及回归再时效处理。通过显微组织结构观察、硬度分析、XRD、DSC、强度分析等手段,研究了不同时效处理对其组织性能的影响。结果表明:7075合金经120℃/24 h单级时效处理后,合金在120℃呈现极佳的热稳定性,细小且高密度的η'基地析出,增大合金强度,最高可达680 MPa,但对应力腐蚀较为敏感。双级时效可改善合金的应力腐蚀敏感性,但强度有所降低。回归再时效处理兼顾了T6单级时效和双级时效的优点,维持高强度的同时,提高抗腐蚀能力。

The T6 aging, two stage aging treatment and regression reaging treatment were carried out on high strength aluminum 7075 Alloy. Through the methods of microstrucmre observation, hardness analysis, XRD, DSC, and strength analysis, the effects of aging treatment on the microstructure and performance of 7075 alloy were studied. The results show that： After the 120 ℃/24 h T6 aging treatment, the thermal stability of alloy shows excellent at 120 ℃, and the high density η＇ base precipitation, increases the,strength of the alloy, up to 680 MPa, but is more sensitive to stress corrosion. Two stage aging can improve the stress corrosion sensitivity of the alloy, but the strength of the alloy decreases. Regression and reaging treatment both have the advantages of T6 single stage and double stage aging, so the alloy is not only has the high strength, but also has the good corrosion resistance.