Zr和Ho对Al-6Zn-2.5Mg-1.6Cu铸态合金组织和性能的影响

Effect of Zr and Ho on Microstructure and Properties of As-cast Al-6Zn-2.5Mg-1.6Cu Alloy

通过熔铸方法制备了含Ho和Zr的Al-Zn-Mg-Cu高强铝合金样品,采用金相显微镜、扫描电镜和能谱分析仪观察和分析合金的组织及成分,采用显微硬度计、涡流电导仪及拉伸试验等方法对合金的性能进行了研究。结果表明,同时添加Ho、Zr后,合金组织显著细化,且杂质减少,晶界净化。当加入0.5%Ho、 0.2%Zr时,合金的力学性能最优,其抗拉强度为221 MPa,伸长率为3.83%。当加入0.5%Ho时,合金的硬度、电导率下降,但再加入Zr后,随着Zr含量的增加,硬度逐渐增加,而电导率呈缓慢降低的趋势。综合考虑合金的组织和性能,合金中Ho、Zr的最佳加入量应分别为0.5%、0.2%。

Al-Zn-Mg-Cu alloy samples containing Ho and Zr were prepared by melting casting.The microstructure and composition of the alloy were observed and analyzed by means of metallographic microscope,scanning electron microscope and energy spectrum analyzer.The properties of the alloy were studied by means of microhardness tester,eddy current conductometer and tensile test.The results show that the microstructure of the alloy is refined after alloying with Ho and Zr elements,the impurity decreases and the grain boundary is purified.When 0.5%Ho and 0.2% Zr are added into alloy,the mechanical properties of the alloy are optimal,the tensile strength is 221 MPa and the elongation is 3.83%.When 0.5%Ho is added,the hardness and conductivity of the alloy decreased,but when Zr is added,the hardness gradually increased with the increase of Zr content,while the conductivity show a slow downward trend.Considering the microstructure and properties of the alloy,the optimal amount of Ho and Zr in the alloy should be 0.5% and 0.2%,respectively.