Al-5.87Zn-2.07Mg-2.42Cu合金形变热处理过程的组织与性能演变

Study on Microstructures and Mechanical Properties of Al-5. 87Zn-2. 07Mg-2. 42Cu Alloy During Final Thermomechanical Treatment

通过维氏硬度试验、力学性能试验以及透射电镜观察,研究了Al-5.87Zn-2.07Mg-2.42Cu合金在最终形变热处理(固溶—预时效—变形—终时效)过程中的组织演变和力学性能,并优化出最适宜的工艺制度。结果表明,Al-5.87Zn-2.07Mg-2.42Cu合金最适宜的形变热处理工艺为480℃/1 h+100℃/8 h+30%+120℃/10 h。100℃/8 h预时效处理后,合金基体内弥散析出大量细小的沉淀相。经30%冷变形引入位错后进行120℃/10 h终时效处理,析出相数量增多且尺寸增大。最终形变热处理后合金的硬度、抗拉强度和屈服强度分别为200 HV、645 MPa和621MPa,分别比T6态合金的增加了19 HV、67 MPa和110 MPa。

The microstructures and properties of Al-5. 87 Zn-2. 07 Mg-2. 42 Cu alloy during the final thermomechanical treatment（ FTMT） were studied by Vickers hardness test,mechanical property test and transmission electron microscope observation. The results show that the optimal FTMT was 480 ℃/1 h ＋ 100 ℃/8 h ＋ 30% ＋ 120 ℃/10 h. A large number of fine precipitates had been formed in the matrix when pre-aged at 100 ℃/8 h. Then dislocations were introduced by the 30% cold rolling. Finally,both the volume fraction and average radium of the precipitates were increased after aging at 120 ℃/10 h. The Vickers hardness,tensile strength and yield strength of the FTMT condition were 200 HV,645 MPa and 621 MPa,which were higher than those of the T6 case by 19 HV,67 MPa and110 MPa,respectively.