摘要
主要讨论了熔炼室真空度,钼-铌合金原料棒化学成分和尺寸规格,熔炼速度,搅拌速度等对单晶制备的影响。试验结果表明,熔炼室残余压力值低于3.0×10-2Pa时,区熔过程能稳定制备出钼-铌合金单晶。高温真空烧结钼-铌合金烧结条由于C、O等杂质含量过高,区域熔炼时放气严重,极大地破坏了熔炼室高真空而未能直接生长制备出单晶,但经两次电子束熔炼获得的Ф12mm￣Ф17mm原料棒C含量降为63×10-6,O含量仅为14×10-6,区熔时熔炼室真空度较高,能稳定地生长制备出Ф31mm×735mm的大尺寸钼-铌合金单晶,而直径超过Ф18mm或小于Ф11mm原料棒则未能获得钼-铌合金单晶。此外,熔炼速度和搅拌速度也是非常关键的工艺参数。本试验得出,原料棒在熔炼速度为0.4￣4.0mm/min,搅拌速度为1.0～20r/min的条件下能稳定制备出高质量钼-铌合金单晶。
Influences of vacuum （or residual pressure） in the melting chamber, chemical composition and specifications of Mo-Nb alloy feedstock bar, growing rate, rotation rate on processing Mo-Nb alloy single crystal have been discussed in detail. The results show that the Mo-Nb alloy single crystal has been stably processed with the residual pressure in the melting chamber less than 3.0× 10^-2 Pa. The billets by vacuum sintering, due to high gaseous and metallic impurities contents, where C, O are 160 wtppm and 1000 wtppm respectively, can＇t be directly processed single crystals on 20KW electron beam floating zone melting furnace. The feedstock bars of Φ12-17mm in diameter got by twice electron beam melting with less impurities contents than those of billets, where C, O are 63×10^-6 and 14×10^-6 respectively, can be stably processed single crystals with specification of Φ31 mm×735 mm. However, feedstock bars being less than 11 mm or exceeding 18 mm in diameter can＇t be processed single crystals. Otherwise, the technique parameters of growing rate and rotation rate are very crucial to process perfect Mo-Nb alloy single crystal. On analysizing the results, the perfect Mo-Nb alloy single crystal can be stably processed with the following parameters of growing rate at 0.4-4.0 mm/min and rotation rate at 1.0-20 r/min.
出处
《铸造》
EI
CAS
CSCD
北大核心
2006年第3期225-229,共5页
Foundry
关键词
钼-铌合金
单晶
电子束区域熔炼
制备工艺
Mo-Nb alloy
single crystal
electron beam floating zone melting
processing technique
