Microstructural effects in Modeling the flow behavior of single-crystal superalloys

The deformation behavior of a [001]-oriented single-crystal superalloy (CMSX-4) having a high volume fraction of regularly arrayed cuboidal gamma' precipitates was simulated using a strain-gradient-dependent plasticity description for the gamma matrix and an anisotropic elasticity description for the gamma' precipitate. A unit-cell mesh was adopted to represent the gamma/gamma' microstructure. Numerical studies focused on clarification of the cause of the tension-compression (T-C) asymmetry in single-crystal superalloys. The numerical results suggest that the deformation-constraint effect induced by the gamma/gamma' geometry gives rise to a T-C asymmetry that is different in both sign and magnitude for the elasticplastic transition regime and the fully plastic regime.