Mn对改善A356合金中Fe相有害作用的研究

Study on Improvement of Manganese on Neutralizing Detrimental Effect of Fe Phase in A356 Alloy

采用光学显微镜、X射线衍射仪和INSTRON材料试验机等,研究Mn对高Fe含量的A356合金中Fe相的中和作用,讨论Mn加入量对合金的组织和力学性能的影响。实验结果表明,添加Mn能将粗大针状Fe相转变为汉字状Fe相,但过量加入会导致Fe相总的体积含量增加,形成鱼骨状Fe相。合金的抗拉强度和伸长率亦随Mn加入量的增加呈先升后降趋势,当wMn/wFe为1.1时达到最大值。经T6热处理能进一步提高A356合金的力学性能。

The neutralization effect of manganese on the Fe phase in A356 alloy with high Fe content was investigated by OM, XRD and INSTRON 5882 EUMTS, and the effeet of Mn content on the microstrueture and mechanical properties of A356 was also analyzed. The results show that the addition of Mn can transform coarse needle-like Fe phase into Chinese script shape, but excessive Mn increase the total volume amount of Fe-rich intermetallic phases and lead to the formation of fishbone-like Fe phase. Both tensile strength and elongation of the alloy show the tendency of first rise and then drop with the increase of Mn addition. The optimized mechanical properties can be obtained at WMe/WFe=1.1. After T6 heat treatment, the mechanical properties of A356 alloy further improves.