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采用金相显微镜和QUANTA-400型环境扫描电子显微镜对添加稀土和未加稀土的A6MOLY合金铸态组织和夹杂物进行了观察,并探讨稀土的作用机理。结果表明,A6MOLY合金中添加稀土后,魏氏组织减弱,晶粒有所细化,夹杂物的尺寸减小,形状由不规则变为圆粒状,分布趋于弥散。稀土的合金化作用改善了A6MOLY合金的铸态组织。A6MOLY合金中加入稀土,形成高熔点的稀土夹杂物。由于稀土的吸附作用及稀土夹杂物的非均质晶核作用,阻止了夹杂物的进一步长大,使夹杂物变得细小圆整、弥散分布。
The as-cast microstructure and inclusions of A6MOLY alloy with or without rare earth and rare earth were observed by optical microscope and QUANTA-400 environmental scanning electron microscope. The mechanism of action of rare earth was also discussed. The results show that the addition of rare earth to A6MOLY alloy weakens the structure of Widmanstalls, the grains are refined, the size of inclusions is reduced, and the shape changes from irregular to round and the distribution tends to disperse. Alloying of rare earth improves the as-cast microstructure of A6MOLY alloy. A6MOLY alloy by adding rare earth, forming a melting point of rare earth inclusions. Due to the adsorption of rare earths and heterogeneous nucleation of rare earth inclusions, the further growth of inclusions is prevented, and the inclusions become small and round and dispersed.