Engineering grain boundary sliding and cavitation effects in superplastic alloys employing thermodynamics
Por:
Galindo-Nava E.I., Torres-Villaseñor G., RiveraDiazdelCastillo, PEJ
Publicada:
1 abr 2015
Resumen:
Plastic deformation by grain boundary sliding in superplastic alloys is described by a novel thermostatistical approach. The Gibbs free energy for cavity formation at moving grain boundaries is obtained. It equals the competition between the stored energy at the boundaries and the energy dissipated by grain boundary sliding. The latter is approximated by an entropy term induced by moving dislocations to facilitate boundary displacement. Strength loss evolution is estimated from the cavity evolution rate. The theory describes superplastic behaviour of Zn22Al, Zn21Al2Cu and Mg3Al1Zn for various temperatures, strain rates, grain sizes, and specimen geometries. Transition maps are defined for finding the optimal conditions for achieving superplastic behaviour in terms of composition, temperature, geometry and strain rate. © 2015 Institute of Materials, Minerals and Mining.
Filiaciones:
Galindo-Nava E.I.:
Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, United Kingdom
Torres-Villaseñor G.:
Univ Nacl Autonoma Mexico, Inst Invest Mat, Mexico City 04519, DF, Mexico
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