(上海交通大學(xué) 材料科學(xué)與工程學(xué)院，上海 200030)
摘 要: 研究了高密度脈沖電流對過共晶Al-19Si合金凝固組織的影響。結(jié)果表明：未經(jīng)任何處理的試樣凝固組織中含有大量的長桿狀初生Si，其長寬比較大，且共晶Si尺寸較大；而經(jīng)過高密度脈沖電流處理后，凝固組織中初生Si轉(zhuǎn)變?yōu)閴K狀，長寬比顯著減小，共晶Si呈短桿狀，尺寸較小，另外在試樣的局部存在初生Si晶粒破碎現(xiàn)象，這是高密度脈沖電流在熔體內(nèi)部產(chǎn)生不平衡的電磁力而導(dǎo)致不平衡剪切的結(jié)果。
關(guān)鍵字: Al-19Si合金；凝固組織；高密度脈沖電流處理；電磁力
current on solidification structure
of hypereutectic Al-19Si alloy
（School of Materials Science and Engineering，
Shanghai Jiaotong University，Shanghai 200030， China）
Abstract:The influence of high density pulse electric current(HDPEC) on the solidification structure of hypereutectic Al-19Si alloy was studied. The results show that there exist lots of primary Si phases with long pole shape in the solidification structure when the specimen are not treated by HDPEC，and the aspect ratio of Si grain is larger. The size of eutectic Si is large. However，through H OPEC, the morphology of the primary Si phases changes into blocky structure greatly，and the aspect ratio of Si grain becomes smaller. The eutectic Si phases appear short pole，and the size of them decreases obviously. Moreover，there exist some smallest and broken Si grains in certain area of the specimen, which is resulted from the non-equilibrium distribution of the electric magnetic force existed in the melt.
Key words: Al-19Si alloy; solidification structure; high density pulse current; electric magnetic force
