Three dimensional dislocation-based crystalline constitutive formulation for ordered intermetallics

A three dimensional multiple-slip crystal plasticity constitutive formulation that is coupled to the temperature dependent evolution of mobile and immobile dislocation densities has been developed for a more detailed understanding of the deformation modes of ordered intermetallics. The predictive capabilities and accuracy of the constitutive formulation and the finite-element computational scheme have been investigated by simulating experimental results for single crystal nickel aluminide. There is good agreement between the computational and the experimental results. The use of the proposed constitutive formulation also resulted in accurate predictions of the increased strength of nickel aluminide as a function of increases in temperature. This is a strong indication that the dislocation based constitutive formulation and the finite-element algorithm result in accurate predictions of the deformation and strength response of monocrystalline nickel aluminide for the strain range and temperatures used in the experimental study. Based on these results, this dislocation based constitutive formulation will be used in future studies to investigate the effects of dislocation motion, interaction, and transmission on finite strain deformation and failure modes in intermetallic materials separated by high angle CSL and random GBs.