钼-铌合金原料品质对单晶制备的影响

Influence of Feedstock Qualities on Processing Mo-Nb Alloy Single Crystal

主要讨论了钼-铌合金原料品质，包括烧结条的制备、原料的化学成分、原料棒的尺寸规格等对单晶制备的影响。结果表明：高温真空烧结钼-铌合金烧结条由于C、O等杂质含量过高，在20kW电子束悬浮区域熔炼炉上区域熔炼时未能直接生长制备出单晶，但其经过两次电子柬熔炼获得的Φ（12～17）mm原料棒C元素质量分数降为6．3×10^-3％、O元素质量分数降低了近2个数量级，仅为1．4×10^-3％，能稳定地生长制备出Φ31mm×735mm的大尺寸钼-铌合金单晶，而直径超过Φ18mm或小于Φ11mm原料棒在区域熔炼时未能获得钼-铌合金单晶。

Influence of feedstock qualities of Mo - Nb alloy, including its preparation of sintering billet, chemical composition and specifications, on processing single crystal is discussed in detail. The results show that Mo - Nb alloy billets prepared by vacuum sintering, due to high impurities content, can not be directly process single crystals on 20 kW electron beam floating zone of melting furnace. The feedstock bars of Φ（ 12 - 17） mm in diameter obtained by twice electron beam melting with less impurities content, can stably process single crystals with specification of Φ31 mm ×735 ram. However, feedstock bars less than 11 mm or over 18 mm in diameter can not process single crystals.