Plasticity enhancement mechanisms in MoSi2

Low temperature plasticity enhancement mechanisms which are operative in body-centered cubic metals and BZ ordered alloys can be observed in MoSi2 in appropriate stress-temperature-strain rate regimes. We illustrate effects of surface films (ZrO2) and dispersoids (TiC) in enhancing plasticity of MoSi2 in the ductile-to-brittle transition range of temperatures, 900-1400 degrees C. We also show, through experiments involving high temperature (1300 degrees C) prestrain, that effective operation of dislocation generation processes can extend the low temperature range to which polycrystalline MoSi2 can be plastically deformed. The dislocation substructures of polycrystalline MoSi2 deformed over this temperature range have also been characterized. The overall results illustrate that approaches to enhance toughness of MoSi2 need not be limited to ductile phases characterized by weak interfaces. (C) 1999 Published by Elsevier Science S.A. All rights reserved.