激光高速熔凝Ni-33%Sn过共晶合金组织演化  

Microstructure Evolution of Ni-33%Sn Hypereutectic Alloy in Laser Rapid Solidification

作　　者：汪志太[1,2] 林鑫 曹永青[1] 黄卫东[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072 [2]南昌航空大学工程训练中心,江西南昌330063

出　　处：《铸造技术》2017年第12期2805-2808,2824,共5页Foundry Technology

基　　金：国家自然科学基金资助项目(51323008;51475380;51271213);国家重点基础研究发展计划资助项目(2011CB610402);国家高技术研究发展计划资助项目(201AA031103);高等学校博士学科点转向科研基金(20116102110016);中国高等学校学科创新引智计划资助项目(08040)

摘　　要：分别采用连续激光及脉冲激光高速熔凝Ni-33%Sn过共晶合金。结果表明,经连续激光熔凝后熔池内组织由α-Ni+β-Ni3Sn规则层片共晶、未完全熔化的β-Ni3Sn颗粒,以及部分重熔的β-Ni3Sn枝晶组成,经脉冲激光熔凝后熔池内为完全的α-Ni+β-Ni3Sn规则层片共晶。两种方式熔凝后,熔池内组织较基材均明显细化,随着激光扫描速度的增大,共晶层片间距逐渐减小。当激光扫描速度达到1 000 mm/s时,仍未出现规则层片共晶向非规则反常共晶组织的转变,结合TMK模型分析,同时与相同生长速度下的深过冷实验对比,揭示快速生长并非产生反常共晶形成的充分条件。The microstructure evolution of Ni-33% Sn hypereutectic alloy during high-speed laser remelted by continuous laser and pulsed laser had been investigated. The results show that after continuous laser remelted, the microstructure consists of（α-Ni＋β-Ni3 Sn） eutectic, β-Ni3 Sn dentritic and partly remelted β-Ni3 Sn particles, whereas it consists of（α-Ni＋β-Ni3 Sn）eutectic after continuous laser remelted. The lamellar eutectic spacing decreases with increasing the scanning velocity, and the lamellar eutectic spacing is reduced significantly after laser rapid solidification. The transition from regular eutectic to irregular anomalous eutectic structure has not appeared when the scanning velocity reach 1 000 mm/s, combine with TMK model and the undercooling under the same growth velocity, revealing that rapid growth is not the sufficient conditions for the formation of anomalous eutectic.

关 键 词：激光高速熔凝 Ni-33%Sn合金 组织演化 

分 类 号：TG21[金属学及工艺—铸造]