Zn含量对AlMgSiCu合金组织和力学性能的影响

使用常规铸锭冶金方法制备了不同Zn含量的AlMgSiCu合金.利用光学显微镜、扫描电镜、拉伸测试和纳米压痕方法研究了Zn含量对铝合金微观组织和力学性能的影响.研究发现Zn元素能够轻微细化AlMgSiCu合金铸态组织.随着合金中Zn含量的增加,铸态铝合金的晶界变宽,晶界析出相增多.Zn的添加未影响铸态合金的相组成和形貌.随Zn含量的增加,铝合金的强度和延伸率呈现先增后降的变化趋势,添加质量分数0.5%Zn可使合金具有最高的强度,而0.75%Zn使合金获得最高延伸率.对含Zn铝合金的纳米压痕测量表明:随着Zn含量的增加,铝合金的弹性模量呈现逐步降低的趋势.

Effect of Zn content on the microstructure and mechanical properties of A1MgSiCu alloys

AlMgSiCu alloys with different Zn contents were fabricated by conventional ingot metallurgy method. The effects of Zn content on the microstructures and mechanical properties of the alloys were investigated by optical microscopy, field emission scanning electron microscopy, tensile testing, and nanoindentation. It is found that Zn cun slightly refine the as-cast grain structure of the alloys. The grain boundaries become broader and more precipitates can form along the grain boundaries with the increase of Zn content; but the addition of Zn does not affect the phase components and morphology of the alloys. When the Zn content increases, the strength and elongation of the alloys increase firstly and then decrease. The alloy with the Zn mass fraction of 0.5% has the highest tensile strength, but the elongation of the alloy with the Zn mass fraction of 0.75% is the largest. Nanoindentation measurement shows that the elastic modulus decreases gradually with increasing Zn content.