Dense nanometric microalloyed molybdenum disilicide synthesized through mechanical and field activation

There has been no theoretical improvements in the high temperature capability of materials used in the hot sections of turbines since 1941 [2]. Exploitation of the nickel based super-alloys to their fullest potential is a result of processing improvement, mainly in the form of vacuum arc melt furnaces [3].; Anton and Shah [4, 5] report based on ultimate tensile strength (UTS), creep strength and oxidation resistance that seven intermetallic compounds with melting points above 1600°C, have been selected as possible replacement materials for high temperature structural materials. These selected compounds are as Nb₃Al, Cr₃Si, Co₂Nb, MoSi ₂, Mo₅Si₃ and Nb₂Al. In the terms of UTS and oxidation resistance, MoSi₂ is the material with the most promise [5].; Before MoSi₂ is set for industrial application, numerous problems have to be solved. High on the list is the brittle to ductile transition at approximately 1000°C. Waghmare et al., from first principles, list elements which introduced at the microalloying level offer the possibility for ductility improvement in MoSi₂ without sacrificing its outstanding high temperature properties. Of the elements listed m their model, the one with the most promise as a softener of MoSi₂ is magnesium. Until now, this compound had not been synthesized. Through a combination of mechanical alloying and spark plasma sintering, we were able to successfully synthesize the compound Mo(Si _2−xMg_x).; Hardness results presented above confirm the predictions of Waghmare et al. in that a substantial reduction in hardness was realized. Material prepared identically, lacking magnesium, displayed a hardness of 2000 Vickers, while material with 5 at% magnesium displayed a hardness of 620 Vickers.; The elements predicted by Waghmare et al. to have the greatest softening potential on α-MoSi₂: Al and Mg substituting for Si and Nb and V substituting for Mg were explored. The results for Mg match the predictions, while the results for Al, Nb and V match the values found in the literature and the model. Thus, the Waghmare et al. model has been fully experimentally validated.