Investigation on the Modification Behavior of A356 Alloy Inoculated by Sr-Y Composite Modifier
In the present paper, DSC, SEM and XRD were used to examine the effects of Sr-Y composite modifier on the microstructure of A356 alloy. After adding Y to A356, YAl3 compounds were formed, and the ex (Al) crystal nucleus was increased. The degree of supercooling caused by Sr-Y composite modificator was higher than Sr modification by 2.7 ℃, which led to nucleation rate increased, which was favorable to refine eutectic structure and eutectic reaction was delayed in maximum extent. The silicon phase in the as-cast A356 alloy modified by Sr-Y composite modifier was granular or flaky, and no large flake eutectic silicon was found and the modification effects was completely compared with using individual Sr modifier. After T6 heat treatment, most eutectic silicon showed grAln-like shape, and the grAln got smaller. At the same time, there was no eutectic silicon with long strip shape a great enhancement in the particle roundness and evenness of Si crystal , the globosity eutectic silicon was also increased. Both the roundness and evenness of grAlned Si crystal were enhanced and globular eutectic silicon was increased, which showed that excellent modification effect was achieved.
eutectic-silicon composite modifier degree of supercooling
Lin Xiaoping Su Hui Dong Yon
School of Materials Science and Engineering, Northeastern University at Qinhuangdao, Qinhuangdao 066004 , China
国际会议
69th World Foundry Congress(第69届世界铸造会议 WFC 2010)
杭州
英文
204-208
2010-10-16（万方平台首次上网日期，不代表论文的发表时间）