喷射成形Al-Zn-Mg-Cu合金回归再时效过程的XRD分析

XRD Study on Retrogression and Re-aging of Spray Formed Al-Zn-Mg-Cu Alloy

采用拉伸测试、电导率测量,X射线衍射(X-ray diffraction,XRD)分析以及点阵常数测量等方法对喷射成形7075铝合金回归过程中的拉伸性能、导电性能以及溶质元素与强化析出相的析出程度和演变过程进行研究。结果表明,在回归再时效处理过程中,采用合适的回归温度与时间,可有效改善合金的力学和导电性能。经120℃预时效16 h后的喷射成形7075铝合金,通过200℃高温回归8 min及再时效处理,其抗拉强度、屈服强度、伸长率和电导率分别为791 MPa、736 MPa、8.5%和22.6 MS/m,合金综合性能良好。通过XRD分析及α-Al基体晶格常数的精确测量,能更好地表征溶质元素与析出相的回溶和析出,以及回归与再时效后析出相的回溶和析出程度,指导7075合金回归处理制度的优化和选择。

The mechanical properties, conductivity, precipitation behavior and evolution process of elements and phases of spray formed 7075 alloy during retrogression are studied by tensile test, electric test, X-ray diffraction （XRD） analysis and lattice parameter test. The results show that the mechanical properties and conductivity could be effectively improved by the suitable retrogression temperature and time during the retrogression treatments. The tensile strength, yield strength, elongation and conductivity of the spray formed 7075 alloy after pre-aging at 120℃ for 16 h, retrogression at 200℃ for 8 min and re-aging at 120℃ for 24 h are 791 MPa, 736 MPa, 8.5% and 22.6 MS/m respectively. According to the XRD analysis and the accurate measurement of lattice parameter, the re-dissolution of elements and the precipitation of phases were able to be represented preferably. And due to optimizing and choosing the RRA treatment of 7075 alloy, the regularity of the re-dissolution and the precipitation of elements and phases were researched.