Er对AC7A铝镁合金铸态组织和力学性能的影响

Effect of Er on Microstructures and Mechanical Properties of As-cast AC7A Al-Mg Alloys

采用铸锭冶金法制备AC7A铝镁合金和添加稀土的AC7A合金,通过金相显微镜(OM)、X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)分析和力学性能测试,观察分析了稀土Er元素在AC7A铝镁合金铸态组织中的存在形式及其含量对力学性能的影响。结果表明,稀土Er元素除了固溶在α-Al基体中,还会析出大量的初生Al3Er相。这些析出相在合金结晶时可以作为α(Al)的非均匀形核质点,降低形核功,明显细化铸造组织,使得AC7A合金的力学性能有一定程度的提高。

By means of metallographic microscope(OM), X-ray diffraction(XRD), scanning electron microscopy(SEM),energy spectrometer(EDS) and mechanical properties test, the influence of the presence and content of Er on the mechanical properties of AC7A Al-Mg alloy was studied. The results show that in addition to solid solution in α-Al matrix,a large amount of primary Al3Er phase is precipitated. These precipitated phases can be used as non-uniform nucleating particles of α-Al during the crystallization of the alloy, which can reduce nucleating work, refine casting structure and improve the mechanical properties of AC7A alloy to a certain extent.