变质及熔体处理对过共晶铝硅合金组织的影响

摘要

为了研究变质及熔体处理对过共晶铝硅合金组织的影响,采用光学显微镜、扫描电子显微镜等技术研究了Cu-14％P(质量分数)磷铜变质、Al-10％ RE(质量分数)混合稀土变质以及熔体处理的过共晶铝硅合金组织变化特点.结果表明,熔体处理未能使初晶硅细化,但出现了部分共晶组织被初晶硅晶粒包裹的现象;磷铜变质剂对初晶硅有良好的细化变质作用,组织弥散细小,尖锐的棱角变得圆滑.Al-10％ RE(质量分数)混合稀土变质剂对初晶硅与共晶硅都有一定的细化作用,但对初晶硅的变质效果不如Cu-14％ P(质量分数)变质剂,且变质不均匀,而对共晶硅的细化效果优于磷铜变质剂的细化效果.%In order to investigate the effect of modification and melt treatment on the microstructures of hypereutectic Al-Si alloy,optical microscope (OM) and scanning electronic microscope (SEM) were used to observe the changes of the microstructures modified by Cu-14％ (mass fraction)P alloy,Al-10％ (mass fraction) RE alloy,and by melt treatment process,respectively.The results show that the melt treatment could not refine the primary Si,but partly eutectic Si grains were enclosed by primary Si grains in melt treatment hypereutectic Al-Si alloy.The primary Si was greatly refined by Cu-14 wt.％ P modification in the hypereutectic Al-Si alloy,and the sharp corners of the primary Si was inactivated,and its size was finer.The Al-10％ (mass fraction) RE modification had a certain extent effect on the refinement primary Si and eutectic Si,but the refining effect on primary Si was less than Cu-14(mass (r)action)％ P alloy of that,and on eutectic Si was better than it.