7075铝合金对AZ91镁合金组织和性能的影响

Effect of 7075 Al Alloy on Microstructures and Mechanical Properties of AZ91 Mg Alloy

为了研究7075铝合金对AZ91镁合金组织与性能的影响,采用光学显微镜、扫描电镜、X射线衍射仪、万能材料试验机研究了AZ91镁合金的显微组织与力学性能。结果表明:向AZ91镁合金中加入7075铝合金可使该合金的铸态组织明显细化,当7075铝合金含量超过4%(质量分数,下同)时,AZ91镁合金铸态组织中Mg17Al12相数量明显减少,并且组织中生成了Al6Mn新相。合金抗拉强度与延伸率随着7075铝合金加入量的增加而提高,当7075铝合金的加入达到4%,其抗拉强度与延伸率达到最大值,分别为186 MPa和8.2%。

In order to investigate the effect of 7075 aluminum alloy on the microstructure and mechanical properties of AZ91 magnesium alloy, the optical microscope, scanning electron microscope, X-ray diffraction method and universal material testing machine were used to analysis the microstructure and the mechanical properties of AZ91 magnesium alloy. The results indicate that the addition of 7075 aluminum alloy can refine the as-cast microstructure of AZ91 alloy obviously. The volume fraction of Mg17Al12phase is decreased, and A16Mn phase is formed when the addition content of 7075 aluminum alloy exceeds 4%. The tensile strength and elongation of AZ91 magnesium alloy increase with increasing of the addition amount of 7075 aluminum alloy. When the addition of 7075 aluminum alloy is 4%, the tensile strength and elongation of AZ91 alloy are at the maximum value, which are 186 MPa and 8.2%, respectively.