Solidification sequence and as-cast microstructure of a model Pb-Bi-Sn alloy with quasi-peritectic reaction  

作　　者：Gang Liu Qian Yang Cao Wang Zhu-huan Yu Guo-jun Zhang 

机构地区：[1]School of Materials Science and Engineering,Xi’an University of Technology,Xi’an 710048,China [2]School of Materials Science and Engineering,Xi’an University of Science and Technology,Xi’an710054,China [3]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China

出　　处：《China Foundry》2019年第6期399-405,共7页中国铸造（英文版）

基　　金：National Natural Science Foundation of China(No.51604222);China Postdoctoral Science Foundation(No.152064),Strong Industrial Base Project of China(No.TC160A310-18);Xi'an University of Science and Technology for Excellent Young Teachers Research Program(No.2018YQ2-12);Excellent Projects funded by Science and Technology Activities for Overseas Students in Shaanxi Province(No.2018047).

摘　　要：The Pb39 Bi25 Sn36 alloy was directionally solidified at varied withdrawal rates followed by quenching.From metallographic observation,composition analysis and differential scanning calorimetry(DSC)analysis,the solidification sequence of Pb39 Bi25 Sn36 alloy was characterized.The Sn-dendrite is observed as the primary phase during solidification,followed by theβ(Pb7 Bi3)/Sn divorced eutectic.At lower temperatures,theβ(Pb7 Bi3)/Sn binary eutectic is formed in the interdendritic region.However,the quasi-peritectic reaction[L+α-Pb→β(Pb7 Bi3)+Sn]does not occur as the prediction based on ternary phase diagram analysis,which can be attributed to the unequilibrium solidfication condition.Moreover,the as-cast microstructure is significantly refined with the increasing withdrawal rates.The quenched sample only exhibits the lamellar structure of Sn,β(Pb7 Bi3)and Bi phases.The results can provide instructions to optimize the as-cast microstructure of ternary alloys with quasi-peritectic reaction.The Pb39 Bi25 Sn36 alloy was directionally solidified at varied withdrawal rates followed by quenching. From metallographic observation, composition analysis and differential scanning calorimetry（DSC） analysis, the solidification sequence of Pb39 Bi25 Sn36 alloy was characterized. The Sn-dendrite is observed as the primary phase during solidification, followed by the β（Pb7 Bi3）/Sn divorced eutectic. At lower temperatures, the β（Pb7 Bi3）/Sn binary eutectic is formed in the interdendritic region. However, the quasi-peritectic reaction [L+α-Pb→β（Pb7 Bi3）+Sn] does not occur as the prediction based on ternary phase diagram analysis, which can be attributed to the unequilibrium solidfication condition. Moreover, the as-cast microstructure is significantly refined with the increasing withdrawal rates. The quenched sample only exhibits the lamellar structure of Sn, β（Pb7 Bi3） and Bi phases. The results can provide instructions to optimize the as-cast microstructure of ternary alloys with quasi-peritectic reaction.

关 键 词：quasi-peritectic ALLOY directional SOLIDIFICATION SOLIDIFICATION SEQUENCE 

分 类 号：TG146.12[一般工业技术—材料科学与工程]