镁合金净化技术研究

Study on the Purification Technology of Magnesium Alloy

利用金相分析、电镜、岛津材料试验机等方法研究了不同净化工艺对镁合金力学性能、组织、断口形貌的影响。结果表明 ,对于AZ91镁合金 ,精炼剂的用量不宜超过 3 .5 % ,浇注温度应控制在 72 0～ 730℃。采用熔剂、吹氩和过滤的复合净化处理工艺可以有效清除镁熔体中的夹杂物和气孔 ,使镁合金的性能得到极大的提高。经复合净化处理后的AZ91的σb和δ可分别达到 2 0 6 .1MPa和 5 .2 1 %。金相观察表明 ,净化处理对金相组织无明显的影响 ,不改变AZ91镁合金的断裂机理 。

The effects of several kinds of purification processes on mechanical properties, structure, fracture pattern of magnesium alloy have been studied by metallographic analysis, SEM, SHIMADZU AG material testing machine. The results show that the content of flux should be less than 3.5% and the pouring temperature should be controlled under 720～730℃. The inclusions and pores in magnesium melts can be removed effectively by compound purification processes of flux, blowing Ar, filtration, and the mechanical properties of magnesium alloy can be improved greatly. The σ b and δ of AZ91 can reach 206.1MPa and 5.21% respectively after the above compound purification processes. The metallographic analysis results show that the purification treatment has not obvious effect on metallurgical structure. The fracture mechanism of AZ91 has not been changed, and the fractures are still quasi cleavage crack.