Volume and size effects of intermetallic compounds on the high-temperature oxidation behavior of Mo-Si-B alloys

Abstract

In this study, we investigated the high-temperature oxidation behavior of Mo-Si-B alloys with different volume fractions or sizes of intermetallic compound phases. Mo-Si-B alloys with uniformly dispersed intermetallic compound phases (Mo5SIB2 and Mo3Si) in Mo solid solution matrix phase were fabricated using a novel powder metallurgical route, as introduced in our previous study. An isothermal oxidation test was conducted at 1300 degrees C for up to 10 h. The high-temperature oxidation resistance of Mo-Si-B alloys improved by increasing the volume fraction of intermetallic compound phases; this was a result of the increased amount of protective oxidized layers, which protect the Mo-ss phase from oxidation by covering the surface. In addition, Mo-Si-B alloy with smaller intermetallic compound phases pulverized by high-energy ball milling had better high-temperature oxidation resistance compared to Mo-Si-B alloy with as-synthesized intermetallic compound phases.