固溶处理对Al-9.0Zn-2.8Mg-2.5Cu-0.12Zr-0.03Sc铝合金组织性能的影响

摘要

采用金相显微镜、差热分析(DSC)和透射电镜(TEM)研究复合添加0.03%Sc 与0.12%Zr 及固溶处理对Al−9.0Zn−2.8Mg−2.5Cu合金组织性能的影响，以及添加少量(小于0.1%)的Sc是否能得到高性能铝合金。结果表明：添加0.03%Sc与0.12%Zr可以使Al−9.0Zn−2.8Mg−2.5Cu合金出现“花瓣状”的Al3(Sc,Zr)析出相；Al3(Sc,Zr)粒子对位错有强烈的钉扎作用，明显抑制 Al−9.0Zn−2.8Mg−2.5Cu 合金在均匀化和挤压过程中的再结晶；多级固溶明显优于单级固溶，可以在添加少量Sc(小于0.1%)时，避免Al−9.0Zn−2.8Mg−2.5Cu发生再结晶：(420°C，3 h)+(465°C，2 h)为最佳固溶条件，此时Al−9.0Zn−2.8Mg−2.5Cu−0.12Zr−0.03Sc合金的抗拉强度为777.29 MPa，伸长率为11.84%。%Effects of additions minor contents of 0.03%Sc and 0.12%Zr and solution treatment on microstructure and mechanical properties of Al−9.0Zn−2.8Mg−2.5Cu alloy were studied by metallographic microscopy, differential thermal analysis (DSC) and transmission electron microscopy (TEM), in order to obtain high-performance Al alloys. The minor additions of Sc (less than 0.1%) were carried out. The results show that with the additions of 0.03% Sc and 0.12% Zr, the petaloid Al3(Sc,Zr) precipitated phases occur in Al−9.0Zn−2.8Mg−2.5Cu alloy, and Al3(Sc,Zr) particles obviously hinder the recrystallization of Al−9.0Zn−2.8Mg−2.5Cu alloy during homogenizing and extruding processes due to their strong pinning effect on dislocation. Multi-stage solution is better than single solution, for it can avoid recrystallization of Al−9.0Zn−2.8Mg−2.5Cu alloy with the minor contents of Sc (less than 0.1%). The proper solution treatment is (420 °C, 3 h)+(465 °C, 2 h) under which Al−9.0Zn−2.8Mg−2.5Cu−0.12Zr−0.03Sc alloy obtains a tensile strength of 777.29 MPa and a elongation of 11.84%.