稀土对铝硅合金凝固过程的变质作用

Modification Effects of RE on Solidification of Al-Si Alloys

采用热分析、籽晶植入、表面分析等方法,全面考察了RE对Al-Si合金凝固过程的作用。结果表明,1%RE的加入量己影响了Al-Si相图,使共晶凝固点和共晶熔点都降低,但RE不影响出相生长的晶体学特性,RE也不在出相的生长表面上吸附。据此,探讨了RE对Al-Si合金的变质作用机理,得出,RE对Al-Si合金的变质作用,在于其在共晶生长界面前的溶质再分配。

The effects of RE on the solidification processing of Al-Si alloys were Studied by using thermal analysis,metalloscopy XPS and AES surface analysis. Results showed that, with addition of up to 1 % RE, the phase diagram of Al-Si oyStem altered, decreasing markedly the eutectic arrest and melting point, but the epitaxial growth features of silicon phase was not affected. Results also showed that there is no absorption of RE on the growth surface, (111)si of silicon phase. The modification mechanism of RE on Al-Si alloys was discussed. It is Suggested that the modification effects of RE on Al-Si alloys is due to solute redistribution in front the eutectic growth interface, thus rendering the eutectic structure passible to modify.