Mo-Nb合金单晶的显微组织

通过金相(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)和透射电镜(TEM)等方法,研究了Mo-Nb合金单晶棒材的显微组织。结果表明,电子束悬浮区域熔炼法生长的Mo-Nb合金单晶内部存在丰富的亚晶组织,且随着单晶生长速度增大,单晶内部亚晶尺寸减小。同时,晶体内部出现生长纹线。而Nb元素的偏析度随着单晶生长速度的增大而增大。随着合金元素Nb含量增加,单晶内部亚晶尺寸减小。经过高温真空退火后,单晶内部亚晶尺寸发生改变。

Microstructures of Mo-Nb Alloy Single Crystals

The microstructures of Mo-Nb alloy single crystals grown by electron beam floating zone melting were studied using the optical metallograph (OM), scanning electron microscopy (SEM), electron back scatter diffraction (EBSD) and transmission electron microscopy (TEM). The results show that molybdenum-niobium alloy single crystals consist of a mass of sub-grain microstructure. With the increasing of the growth rate of the single crystals, the size of the sub-grain decreases and the growth striations appear at the same time. But the degree of segregation of the alloying element niobium increases with increasing of the growth rate. The increasing content of alloying element Nb also decreases the size of the sub-grain. The size of the sub-grains changes after high temperature annealing process in vacuum.