机械合金化W-Cu固溶体的形成机理

Mechanisms of W-Cu solid solution formed by mechanical alloying

采用W-15%Cu和W-25%Cu两种复合粉,开展了机械合金化诱导W-Cu固溶度扩展机制的研究.研究表明:两种粉末经8 h高能球磨后,Cu固溶入W中形成固溶体.机械合金化诱导W-Cu固溶度扩展的主要机制,一方面是高能球磨过程中所引起的粒子纳米化,形成大量的纳米界面,许多原子“储存”在这些纳米晶界上,诱导W-Cu固溶浓度扩展.另一方面是机械合金化过程晶格严重畸变,晶粒内部生成高密度缺陷,成为溶质快速扩散的网络通道,诱导过饱和固溶体的形成.

Two mixture powders of W- 15wt. % Cu and W -25wt. % Cu were used to test the extension of solid solubility of W - Cu induced by mechanical alloying. The results show that Cu atoms dissolved within W crystal lattice and formed a solid solution after only solid solubility of W - Cu result from two reasons. ball milling milling for 8 h. The main mechanisms for the extension of One is the formation of nano-structural crystalline during , which results in an increase in the grain boundary. A large volume fraction of atoms stored in the grain boundaries are expected to enhance the extension of W - Cu solid solubility. The other is that crystal lattices are heavily deformed and a large amount of structural defects are introduced during milling, which provides diffusion channels for the solute atoms rapid diffusion, resulting in the formation of supersaturated solid solutions. The atom structural model is provided to understand the mechanism of the extension of W - Cu solid solubility.