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加入0.10%~0.30%的稀土Sc对A356合金中进行变质处理,以研究稀土Sc对A356合金微观组织和力学性能的作用。结果表明,加入Sc可以使A356合金微观组织中的初生α相显著细化,由粗大的树枝晶变为细小、无定向的枝晶,并且形态变得圆整,出现了大量的蔷薇状和颗粒状的α相。Sc加入量为0.20%时,对α相的细化效果最理想;同时,Sc还使A356合金微观组织中的共晶Si尺寸显著减小,由粗大的针状变为蠕虫状和点状。加入0.20%的Sc的A356合金,其铸态下抗拉强度为210.58 MPa,屈服强度为100.48 MPa,伸长率为6.5%,硬度(HB)为67.5。
The addition of 0.10% ~ 0.30% of rare earth Sc modified A356 alloy to study the effect of rare earth Sc on the microstructure and mechanical properties of A356 alloy. The results show that adding Sc can significantly refine the primary α phase in the microstructure of A356 alloy from coarse dendrites to fine, non-oriented dendrites, and the morphology becomes round, a large number of rosette and particles appear Like alpha phase. When the content of Sc is 0.20%, the refining effect of α phase is the best. At the same time, Sc reduces the size of eutectic Si in the microstructure of A356 alloy from coarse acicular to worm-like and punctate. The addition of 0.20% Sc alloy A356, the as-cast tensile strength of 210.58 MPa, yield strength of 100.48 MPa, elongation of 6.5%, hardness (HB) of 67.5.