Improved creep resistance of Mo-V-Si-B alloys with a density below 8 g/cm³

Abstract

Improving the efficiency of turbines for power plants and aircraft engines is an increasingly important research subject. Ternary Mo-Si-B alloys, consisting of a molybdenum solid solution (Moss) phase and two intermetallic phases Mo5SiB2 (T2) and Mo3Si, are able to combine balanced room temperature fracture toughness, high temperature creep strength and good oxidation performance. However, the high density (typically > 9 g/cm3) of this class of alloys is a drawback when used as structural materials for rotating components. In this study, high potential Mo-V-Si-B materials which provide a reduced density by about 17 % as compared with the reference alloy Mo-9Si-8B were investigated. A comparative characterization was carried out on sintered (FAST) and arc-melted Mo-40V-9Si-8B alloys. Compressive creep tests reveal competitive creep resistance of this new type of alloys in the application relevant temperature regime.