钼-钴-硅混合粉末的机械合金化研究

Mechanical Alloying Study of Mo-Si-Co Powder Mixture

摘要:

采用X射线衍射、扫描电镜及透射电镜研究了配比为Mo5-xCoxSi3(x=0．5，l，2)的混合粉末的机械球磨行为。结果表明：随球磨时间延长，混合粉末中首先形成Co，Si在Mo中的过饱和固溶体Mo(Co，Si)，高能球磨大大扩展了硅和钴在钼中的固溶度。进一步延长球磨时间，过饱和固溶体转变成为非晶。在球磨过程中，Mo(Co，Si)的晶粒不断细化，球磨至40h，晶粒尺寸约为8nm。球磨初期，内应力急剧增加。随球磨时间延长，混合粉末的颗粒尺寸增大，40h后，逐渐减小，且形状球化，100h后成为尺寸不超过100nm的球形粉末。

Abstract:

Mechanical milling behavior of Mo Si Co powders has been investigated by using XRD, SEM and TEM techniques. The mixtures of elemental molybdenum, silicon and cobalt powders with a stoichiometry of Mo5 xCoxSi3 (x=0.5,1,2) were milled in a planetary mill up to 100 hours. It was found that three kinds of powder mixtures showed the same trend in the process of mechanical milling. First, Mo (Co, Si) supersaturated solid solution was formed (Moss). High energy milling led to a remarkable expansion of the solubility of Co, Si in molybdenum. The transformation of Moss to an amorphous phase was identified after a longer time milling. In the milling process, the grain size of Mo (Co, Si) decreased gradually and the internal stress increased sharply. After 40 hour milling, the grain size was reduced to about 8 nm. The SEM analysis of milled powders showed that the particle size increased initially with milling time. After 100 hours milling, particles exhibited a spherical morphology and the particle size was reduced to about 100nm.