P-RE复合变质对A392合金中初晶硅的影响  

Effects of RE on the Primary Si Phase in A392 Alloy with P-RE Mixed Modification

作　　者：余焕伟[1] 杨明升 张天清 刘忠侠[1] 赵瑞峰[1] 王明星[1] 刘志勇[1] 翁永刚[1] 

机构地区：[1]郑州大学物理工程学院材料物理教育部重点实验室 [2]登封电厂集团铝合金有限公司

出　　处：《特种铸造及有色合金》2008年第6期480-484,共5页Special Casting & Nonferrous Alloys

摘　　要：通过SEM、XRD等分析手段研究了A392合金的P-RE复合变质效果,重点研究了RE元素在A392合金中的形态、分布及其对初晶硅的细化变质机理。结果表明,使用0.08%的P、1.1%的RE复合变质时效果最好,初晶硅平均直径达到19.4μm。RE能在P细化的基础上进一步细化初晶硅,可能是因为RE在Si生长界面前沿富集,阻碍Si原子的扩散,加大了成分过冷,使其生长界面呈现不稳定状态,限制了初晶硅的长大。过量的RE会导致合金中出现大量的RE富集物,不但会降低初晶硅细化效果,而且还降低合金的力学性能,因此,采用P-RE复合变质时,需要严格控制RE含量。A392 alloy with P-RE mixed modification was investigated by SEM(scanning electron microscope)and XRD(X-ray diffraction),focusing on morphology and distribution of RE element in A392 alloy as well as refinement mechanism on primary Si phase.It is revealed that the primary Si phase can be obviously refined with 0.5%~1.5% RE and P mixed modification,in which the average grain size of primary Si phase reaches up to 19.4μm with 0.08% P and 1.1%RE mixed modification.The RE element can enrich on the growth interface of silicon crystal to restrain the diffusion of Si in alloy melt and to increase the undercooling rate,resulting in destroying the stability of growth interface,which can be responsible for the refinement effects of RE on primary Si phase.However,excessive Re element can result in generation of amounts of RE-enrichment,which can not only be detrimental to the refinement effects on primary Si phase,but also deteriorate the mechanical properties of the alloy.So,the RE content in P-RE mixed modification should be strictly controlled.

关 键 词：A392合金 P-RE复合变质 初晶硅细化 

分 类 号：TG146.21[一般工业技术—材料科学与工程]