Mg与稀土Ce混合添加对A356.2铝合金组织与性能的影响

Effect of Mg and Ce Mixed Addition on the Microstructure and Tensile Property of A356.2 Aluminium Alloy

以汽车用A356.2铝合金为研究对象,利用金相显微镜、扫描电镜和拉伸试验机,研究了Mg、Ce混合添加对A356.2铝合金组织与性能的影响。结果表明:Mg含量的增加,可以激发Ce对A356.2铝合金的细化变质作用;在本次试验条件下,0.35%Mg与0.05%Ce混合添加具有明显的细化变质作用,降低了稀土在铝合金材料中使用的成本门槛;随着冷速的加快,Mg与Ce混合添加对A356.2铝合金性能的影响更加明显;Mg与Ce混合添加可以改善针状α-Fe相的形貌,减少其对A356.2合金的不利影响。建立了Mg和Ce含量、模具温度以及所添加Al-Ti-B含量对A356.2材料屈服强度的数学模型,其预测值与试验数据吻合较好。

The effects of Mg and Ce mixed addition on the microstructure and tensile properties of A356.2 aluminum alloy were investigated via optical microscopy, scanning electron microscopy and tensile property testing machine. The results show that the increased Mg content can excite the grain refinement and modification of Ce in A356.2 alloy, which can reduce the cost of rare earth using in aluminum alloy. Within the condition of this study, a significant refinement and modification effect is obtained with the co-addition of 0.35% Mg and 0.05%Ce, and this effect becomes more obvious with the increased cooling rate. Besides, the negative effect of α-Fe phase is reduced by the morphology changing due to the addition of Mg and Ce. A model containing Mg, Ce, Al-Ti-B contents and the mold temperature is established, and the predicted values agree well with the exoerimental data.