铸造1060/AZ31包铝镁合金界面结构与显微组织

为探索和改善轧制包铝镁合金板的界面结合状况，用气体保护铸造法制备了1060铝板包覆AZ31镁合金铸锭．借助金相显微镜、扫描电镜以及X射线衍射等分析方法，研究了复合铸锭芯材及界面的显微组织和相结构，并进行了硬度测试．发现AZ31镁合金芯材组织由α-Mg基体以及沿晶界分布的不连续网状α-Mg＋p＋Mg17A112共晶体组成，是一种典型的铸造离异共晶组织．铸造包铝镁合金锭界面形成扩散溶解层，扩散溶解层由α-Mg固溶体层、共晶层（α-Mg＋β＋Mg17A112）、β-Mg17A112及A1Mg化合物层组成，形成具有多层结构的冶金结合界面．提出了浇注AZ31熔体的瞬间在1060铝板表面形成“熔池”并快速凝固的界面形成机制．

Microstructure and interfacial configuration of AZ31 magnesium alloy ingots clad by 1060 aluminium

1060 aluminium cladding AZ31 magnesium alloy composite ingots were prepared under gas protection to investigate and improve the interfacial combination.The microstructure,phase constituents and microhardness of the matrix and the interface were studied by use of optical microscopy(OM),scanning electron microscopy(SEM) and X-ray diffraction(XRD).It is found that the microstructure of the as-cast AZ31 magnesium alloy consists mainly of the α-Mg matrix and the typical divorced eutectic of α-Mg and β-Mg17Al12 phases distributed along grain boundaries.A diffusion fusion layer forms in the interface,leading to a complex metallurgical interface with a multilayer of the α-Mg solid solution zone,the eutectic(α-Mg + β-Mg17Al12) zone and the Mg-Al intermetallic compound zone.The Mg-Al intermetallic compounds are made up of β-Mg17Al12 and AlMg.It is proposed that the formation mechanism of the complex interface layer is due to the emergence of a molten bath on the 1060 Al plate surface at AZ31 melt pouring moment and the rapid solidification subsequently.