Third M.I.T. Conference on Computational Fluid and Solid Mechanics June 14–17, 2005  

Mechanism-based constitutive modeling of L12 crystals

Y. Yuan*, D.M. Parks
Department of Mechanical Engineering, MIT, 77 Mass Ave. RM 1-321, Cambridge, MA 02139, USA

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A single-crystal constitutive model of the L12-structure intermetallic compound Ni3 Al is developed, based on recent theoretical developments in dislocation mechanics and on experimental evidence. Hirsch's superkink-bypassing model and Caillard's self-unlocking mechanism have been modified and combined to describe dislocation dynamics in the yield anomaly region. Results of numerical simulations successfully capture major features of temperature dependence of the tensile yield strength and hardening rate over a range of crystallographic orientations.

Keywords:  L12 crystals; Constitutive model; Dislocation mechanism; Superkink

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