电弧喷涂铝涂层/AZ91D镁合金固液复合工艺研究

通过固液复合法实现了电弧喷涂铝涂层与AZ91D镁合金基体之间的结合,并对结合界面的组织、元素和相组成进行了分析。结果表明:对涂层进行表面处理,结合界面容易出现气孔等缺陷。未经处理的涂层和基体之间形成冶金结合界面,并生成相应的金属间化合物。随着浇注温度的升高,扩散区域逐渐变宽,涂层逐渐转化为Al12Mg17和Al3Mg2。对复合材料进行热处理,结合界面组织更加均匀,扩散区域的厚度明显增加。正镁合金作为目前最轻的金属结构材料,在汽车和航空航天等领域起到明显的减重效果,正得到日益广泛的应用。但镁合金耐蚀、耐磨等表面性能较差,也限制了它的大规模应用。在镁合金表面制备一层Mg-Al金属间化合物,可以在不增加镁合金质量的前提下,同时提高其耐蚀和耐磨性能1,2]。目前,研究者往往通过表面技术和热处理在镁合金基体表面制备该化合物。例如,L.Zhu3]等通过对AZ91D镁合金和铝

Study of solid-liquid bonding of arc-sprayed aluminum coatings/AZ91D substrates

The joining of arc-sprayed aluminum coatings to AZ91D substrates was achieved by solid-liquid bonding method, and the microstructures, elements and phases of the interface were analyzed. The results show that hole-defect is usually occurred in the interface after the coatings were cleaned by surface treatment. Metallurgical bonding is formed between the untreated aluminum coating and AZ91D substrate, and intermetallic compound layers are found in the interface. As the pouring temperatures rise, the diffusion regions become larger, and the coatings are gradually transformed into Al12Mg17 and Al3Mg2. The heat treatment on the composite can lead to a uniform structure and a larger diffusion region.