以AZ91D合金为基体,金属铝粉作为主要的合金化元素,自制了性能优良的合金化涂料,利用消失模铸造工艺制备了表面复合材料。在温度780℃、负压度一0.02MPa条件下进行浇注,研究发现在镁合金基体表面有大量的新相生成,利用扫面电镜和电子能谱对组织进行分析,当合金化涂料厚度从0.3mm增加到0.5mm时,复合层的厚度也随之增加,可达到300微米,并且组织均匀、致密。硬度测试和模拟海水腐蚀试验表明,表面复合层最高硬度可以达到基体的3倍左右;并且腐蚀速率与铸态的AZ91D相比降低了5倍左右。
Surface composites was fabricated by evaporative pattern casting technology,in this paper, AZ91D was choosed as the base alloy,and aluminum powder as the alloying element,alloying coating was self-made with a good property. The magnesium alloy melt was poured at 78022 ,negative pressure degree at -0.02MPa,it was found that a great number of new phases were formed on the matrix,the microstructure of surface layer was examined by means of scanning electron microscopy(SEM), energy dispersive X-ray(EDX) anaylsis was used to determine the chemical composition of new phases. The thickness of composite layer increased when alloying coating varied from 0. 3mm to 0. 5mm,moreover,the microstructure became dense and distributed evenly. Micro-hardness and electrochemical properties test were performed, the results indicated that the micro-hardness of composite layer was up to three times of the matrix,corrosion resistance increased about 5 times compared with the matrix.