含微量Zr和Y的Al-Zn-Mg-Cu合金的组织与力学性能

Microstructures and Mechanical Properties of Al-Zn-Mg-Cu Alloy Containning Minor Zr and Y

采用光学显微镜、扫描电镜、X射线衍射和室温拉伸等检测技术研究了含微量锆和钇的Al-Zn-Mg-Cu合金的组织与力学性能。结果表明,在Al-Zn-Mg-Cu合金中复合添加微量(总量为0.35%)锆和钇,铸造组织中出现了Al3Y初生化合物,晶粒细小均匀。合金组织的再结晶被强烈抑制,再结晶组织的体积分数较小,晶粒被细化,合金的强度较单独添加锆或钇显著提高。但由于钇的加入使得基体中残留的较粗大化合物(S相)增多,导致合金的延伸率明显下降。

Microstructures and mechanical properties of Al-Zn-Mg-Cu alloy containning minor Zr and Y were studied by means of optical microscope （ OM ）, scan electron microscope （ SEM）, X - ray diffraction （XRD） and tensile properties measurement. The results indicate that when the total amount of Zr and Y in Al-Zn-Mg-Cu alloy is 0.35%, the compound Al3 Y is found in the as - cast microstructures, and the size of crystal grains is small and homogeneous. The courses of recrystallization is intensively restrained. The volume fraction of recrystallized structures is little, and the size of recrystallized grains is fined. The tensile strength of the alloy is higher than that containing only Zr or Y. However, as the coarser rudimental S phase compounds in the microstructure increase with the addition of minor Y, elongation of the alloy decreases evidently.