TiO2对镁合金废旧料组织性能的影响

Effect of TiO_2 on the Structure and Properties of Magnesium Alloy Wastes

利用等离子发射光谱仪、金相分析、电镜、岛津材料试验机等方法研究了含TiO2的熔剂对镁合金废旧料的力学性能、组织、断口形貌的影响。研究发现,对于AZ91镁合金废旧料,使用含TiO2的熔剂除了可以有效清除镁熔体中夹杂物外,还可将镁废旧料中的Fe含量降到0 0056%以下。试验结果表明,TiO2有助于使γ相成粒状或小岛状析出,并具有较强的细化晶粒的效果。采用含TiO2的熔剂净化处理后的AZ91镁合金废旧料的σb和δ可分别达到188 5MPa和4 13%,其性能达到了AZ91新料的水平。金相观察结果表明,净化处理对断口形貌无明显影响,不改变AZ91镁合金的断裂机理,断口均成准解理断裂。

The effects of the fluxes containing TiO2 on the mechanical properties, structure, fracture pattern of magnesium alloy wastes have been studied by ICP spectroscopy, metallographic analysis, SEM and SHIMADZU AG material testing machine. It is discovered that for AZ91 magnesium alloy, the fluxes containing TiO2 not only can remove the inclusions in Mg melt effectively, but also can decrease the Fe content of magnesium alloy wastes to below 00056%. The results show that TiO2 is helpful to the precipitation of γ phase in granular or small island shape and the TiO2 can refine the grain size effectively. The σband δ of AZ91 wastes can reach 1885MPa and 413% respectively after the purification by the fluxes containing TiO2. 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.