Al涂层/AZ91镁合金复合铸造界面的研究

Study on the Composite Casted Interface of Al Coating/AZ91 Magnesium Alloy

对型芯预喷涂一层Al涂层,将AZ91镁合金液浇注到铸型中实现基体和涂层的结合,对凝固后的结合界面组织和相组成进行分析。结果表明,AZ91镁合金液和Al涂层表面的氧化物发生反应,实现了界面间的润湿,形成冶金结合界面。该界面包含3个扩散层:镁合金基体一侧为(Al12Mg17+δMg)共晶组织;中间层为Al12Mg17金属间化合物;Al涂层一侧为Al3Mg2金属间化合物,并弥散分布着一些氧化物。试验结果证明,通过复合铸造的方法可以实现Al涂层和镁合金基体的冶金结合。

Pure aluminium coating was pre-sprayed on the surface of core. The molten AZ91 magnesium alloy was poured into the mold to achieve the combination of substrates and coatings. The solidificated microstructures and phases of the interface were analyzed. The results show that liquid AZ91 magnesium alloy reacts with the oxide on the surface of Al coating to achieve the wetting between the interfaces and the formation of metallurgical bonding interface. The interface consists of three diffusion layers, which are (Al12Mg17+δMg) eutectic structure on the side of magnesium alloy matrix, Al12Mg17 intermetallic compound in the middle layer and Al3Mg2 intermetallic compound with oxides dispersion on the aluminum coating side. It ’s confirmed that metallurgical bonding between Al coating and magnesium alloy matrix can be achieved by composite casting.