Primary dendrite growth of Ni_3Sn intermetallic compound during rapid solidification of undercooled Ni-Sn-Ge alloy  

作　　者：WANG WeiLi QIN HaiYan XIA ZhenChao WEI BingBo 

机构地区：[1]Department of Applied Physics, Northwestern Polytechnical University, Xi＇an 710072, China

出　　处：《Chinese Science Bulletin》2012年第9期1073-1077,共5页

基　　金：supported by the National Natural Science Foundation of China (51101123 and 50971105);the Fundamental Research Fund of Northwestern Polytechnical University (JC201050)

摘　　要：Liquid Ni-31.7%Sn-2.5%Ge alloy was highly undercooled by up to 238 K(0.17TL) with glass fluxing and drop tube techniques.The dendritic growth velocity of primary Ni3Sn compound shows a power-law relation to undercooling and achieves a maximum velocity of 380 mm/s.The addition of Ge reduces its growth velocity as compared with the binary Ni75Sn25 alloy.A structural transition from coarse dendrites into equiaxed grains occurs once undercooling exceeds a critical value of about 125 K,which is accompanied by both grain refinement and solute trapping.The Ni3Sn intermetallic compound behaves like a normal solid solution phase showing nonfaceted growth during rapid solidification.Liquid Ni-31.7%Sn-2.5%Ge alloy was highly undercooled by up to 238 K （0.17TL） with glass fluxing and drop tube techniques. The dendritic growth velocity of primary Ni3Sn compound shows a power-law relation to undercooling and achieves a maximum velocity of 380 mm/s. The addition of Ge reduces its growth velocity as compared with the binary Ni75Sn25 alloy. A structural transition from coarse dendrites into equiaxed grains occurs once undercooling exceeds a critical value of about 125 K, which is accompanied by both grain refinement and solute trapping. The Ni3Sn intermetailic compound behaves like a normal solid solu- tion phase showing nonfaceted growth during rapid solidification.

关 键 词：金属间化合物 合金相 深过冷 枝晶生长 凝固过程 生长速度 幂律关系 最大速度 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG113.12[金属学及工艺—金属材料]