(NaPO_3)_n对过共晶Al-Si合金初晶硅细化的研究

Effect of (NaPO_3)_n on Refinement of Primary Silicon in Hypereutectic Al-Si Alloys

研究了 (Na PO3) n 对 Al- 2 2 % Si过共晶合金初晶硅的晶粒细化作用。结果表明 ,(Na PO3) n对初晶硅的细化效果优于 Cu P,同时 (Na PO3) n 具有共晶硅变质的作用。采用 (Na PO3) n 处理的 Al- 2 2 % Si- 1.0 % Cu- 0 .5 % Mg- 0 .5 % Mn合金的平均抗拉强度可达 2 73MPa。以扫描电镜、电子探针为检测手段研究了 P元素对过共晶 Al- Si合金的 Si晶体的影响。结果表明 ,一方面 Al P作为异质核心细化初晶硅 ,另一方面 ,有 Na同时存在时 ,P的扩散受阻 ,P元素在 Si相生长表面富集 ,阻碍了 Si相生长 ,细化了初晶硅。

Grain refinement of primary silicon in Al Si alloys with (NaPO 3) n has been studied The results show that, the refining effect of (NaPO 3) n on primary silicon is superior to that of CuP, and the former can modify eutectic silicon at the same time The Al 22%Si 1 0%Cu 0 5%Mg 0 5%Mn alloy refined with (NaPO 3) n is characterized with tensile strength up to 273 MPa Effects of phosphorus element on silicon crystal in hypereutectic Al Si alloys have been studied with Electron Scanning Microscope and Electron Probe Moreover, the crystallography and solidification of silicon phase are also discussed On one side, the primary silicon is refined by AlP, which acts as heterogeneous nuclei; on the other side, when sodium element is added at the same time, phosphorus element is difficult to diffuse in melt, and then enriches the growing faces of silicon phase, which prevents the growth of silicon phase and refines the primary silicon