激光区熔定向凝固Gd_5Si_4合金的显微组织特征  

Microstructure of Directionally Solidified Gd_5Si_4 by Laser Zone Remelting

作　　者：张铁邦[1] 胡锐[1] 钟宏[1] 葛光男[1] 李金山[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

出　　处：《稀有金属材料与工程》2012年第10期1837-1841,共5页Rare Metal Materials and Engineering

基　　金：教育部博士点基金(20096102120015)

摘　　要：采用非自耗真空电弧熔炼制备Gd5Si4合金锭,对合金进行了激光区熔快速定向凝固实验,研究了Gd基室温磁致冷材料激光快速定向凝固过程中的组织形成规律及影响因素。利用光学显微镜和扫描电子显微镜对Gd5Si4的稳态生长组织进行了观察,对激光区熔定向凝固合金的一次枝晶间距和激光扫描速率进行拟合的结果表明,Gd5Si4合金的特性与凝固参数之间的关系基本符合Hunt-Lu模型。Gd5Si4 alloy was prepared by the arc-melted method in argon atmosphere.The as-cast alloy was cut and directionally solidified by the laser zone remelting technique.Microstructure evolution and the influencing mechanism of the Gd-based magnetic refrigerant during the rapid directional solidification were investigated.The microstructure originating from steady-state growth was evaluated with optical microscope（OM） and scanning electron microscope（SEM）.The cellular spacing could be expressed as a function of the laser scanning velocity during the rapid solidification.A reasonable agreement is found between the experimental results and the Hunt-Lu numerical model for rapid cellular/dendritic growth.

关 键 词：激光区熔 定向凝固 磁致冷材料 显微组织 

分 类 号：TG113[金属学及工艺—物理冶金]