含钪Al-9.0Zn-2.5Mg-1.2Cu-0.15Zr合金铸态组织与力学性能

As-Cast Microstructures and Properties of Al-9.0Zn-2.5Mg-1.2Cu-0.15Zr Alloys Adding Sc

采用铸锭冶金法制备了Al-9.0Zn-2.5Mg-1.2Cu-0.15Zr、Al-9.0Zn-2.5Mg-1.2Cu-0.12Sc-0.15Zr和Al-9.0Zn-2.5Mg-1.2Cu-0.20Sc-0.15Zr三种合金,采用金相显微镜、扫描电子显微镜和透射电子显微镜,研究了三种合金铸态及不同热处理状态下的显微组织,测试了不同热处理状态下合金的力学性能。结果表明,Sc含量增加可以提高Al-Zn-Mg-Cu-Zr合金的抗拉强度和伸长率,Al-9.0Zn-2.5Mg-1.2Cu-0.15Zr-0.20Sc经固溶和T6处理后,抗拉强度达到774.6 MPa,伸长率为8.3%。其作用机理主要为Sc含量增加,使合金中Al(3 Sc,Zr)引起的细晶强化、亚结构强化和弥散强化更进一步加强。

Three kinds of alloys Al-9.0Zn-2.5Mg-1.2Cu-0.15Zr, Al-9.0Zn-2.5Mg-1.2Cu-0.12Sc-0.15 Zr and Al-9.0Zn-2.5Mg-1.2Cu-0.20Sc-0.15Zr were produced by ingot-metallurgy processing. The tensile mechanical properties of the studied alloys at different treatment conditions were tested and the microstructures of the alloys were studied by optical microscope （OM）, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The results show that enhancement of the content of Sc can improve the tensile strength and elongation of the Al-Zn-Mg-Cu-Zr alloys. After solution and T6, the tensile strength of Al-9.0Zn-2.5Mg-1.2Cu-0.15Zr-0.12Sc is 774.6 MPa, elongation is 8.3%, respectively. The reason is that the higher the content of Sc, the stronger of fine grain strengthening, substructure strengthening and dispersion strengthening by Al3（ Sc, Zr）.