氢等离子体电弧熔炼对稀土金属Gd凝固组织和硬度的影响

Effect of Hydrogen Plasma Arc Melting on Solidification Structure and Hardness of Rare-earth Metal Gadolinium

采用氢等离子体作热源熔化、精炼稀土金属钆(Gd),并采用双辊薄带连铸制备Gd金属带。研究了等离子气中氢气比例、双辊连铸角速度和轧制及热处理工艺对金属Gd凝固组织和硬度的影响。结果表明:增大等离子气中氢气比例、减小双辊连铸角速度,金属Gd中杂质去除率升高,凝固组织晶粒尺寸增大;延长退火保温时间,组织粗化、显微硬度降低。热处理后轧制,金属Gd组织明显细化、显微硬度升高,能满足靶材对晶粒尺寸的要求。

Rare earth metal gadolinium(Gd)was melted and refined by using hydrogen plasma as heat source,and the Gd metal strip was prepared by twin-roll continuous casting.The effects of hydrogen percent in plasma gas,twin-roll continuous casting angular velocity,rolling and heat treatment processes on the solidification structure and hardness of Gd metal were studied.The results showed that the removal rate of impurities in Gd was improved,and its grain size was increased,by increasing the hydrogen percentage and decreasing the casting angular velocity,and that the longer the annealing time,the coarser the grains and the lower the microhardness was.After heat treatment followed by rolling,the microstructure of Gd metal was obviously refined,and the microhardness was increased,thus meeting the grain size requirement for the target.