Synthesis of á-Mo-Mo_5SiB_2-Mo_3Si nanocomposite powders by two-step mechanical alloying and subsequent heat treatment

摘要

A two-step mechanical alloying process followed by heat treatment was developed as a novel approach for fabrication of Mo-12.5mol%Si-25mol%B nanocomposite powders. In this regard, a Si-43.62wt.% B powder mixture was milled for 20 h. Then, Mo was added to the mechanically alloyed Si-B powders in order to achieve Mo-12.5 mol%Si-25 mol%B powder. This powder mixture was further milled for 2,5,10 and 20 h. All of the milled powders were annealed at 1100 °C for 1 h. After first step of milling, a nanocomposite structure composed of boron particles embedded in Si matrix was formed. On the other hand, an a-Mo/MoSi_2 nanocomposite was produced after second step while no ternary phases between Mo, Si and B were formed.