Affordable High Strength Mo-Si-B Alloys for High Temperature Applications

Under this STTR, Deep Springs Technology (DST) in cooperation with Georgia Tech will demonstrate the feasibility of producing affordable high strength Mo-Si-B extrusions based on the Georgia Tech method of ultrasonic spray drying Mo, Si3N4, BN powders, reaction/sintering of the granules at high temperatures to MoSiB composites, and reduction extruding granules at high temperature into dense composite rods. As detailed below, the GT Reaction Sintered (GTRS) process has been demonstrated to provide low interstitial impurities (O, C, N) and to produce both microstructures, oxidation resistance, and high temperature, high strength, ductility competitive with MoSiB composites from other processes. However, high temperature extrusion or similar deformation which imparts substantial mechanical work is believed to be required for MoSiB composites to produce defect free, structural material on an industrial scale with the necessary reliability required for high safety margin applications such as aircraft engines. If successful, developments under this STTR will increase high temperature strength, extent ductility to lower temperatures, maintain reasonable oxidation resistance and low interstitial impurity concentration. These advances would open a range of applications above 1100oC because no reasonable cost metal is available in this arena.