Preparation of MoSi₂-X(X=B, Al, Nb) Alloys by Mechanical Alloying and Pulse Discharge Sintering Process

Abstract

Mechanical alloying and pulse discharge sintering (MA-PDS) process was employed to fabricate MoSi₂ alloys with additions of Al, B or Nb alloy elements. Microstructure and mechanical properties of these alloys were investigated. An exothermic behavior was identified during milling. This process is related to the reaction of each element to synthesize intermetallic MoSi₂. The MoSi₂ alloys fabricated by MA-PDS process showed a very fine microstructure compared to that sintered from the commercial MoSi₂ alloy powders. Significant hardness increase was found due to the refinement of the binary MoSi₂ microstructure. Alloys made from powders milled in air show higher hardness compared to those in Ar gas. This was because of the oxides formed during milling process.