Characterization of phase-specific constitutive behavior based on representative volume element for dual-phase microstructures

Multi-phase alloys may achieve superior performance over single-phase alloys through synergistic combinations of the properties of the individual phases. An understanding of the individual phase properties aids in alloy design and optimization. However, experimental methods for directly characterizing the constitutive behavior of individual phases are limited. In this work, an inverse analysis based on representative volume element (RVE) finite element simulations was used to extract phase-wise constitutive behavior based on micrographs and macroscale constitutive response of two-phase microstructures. Both 2D and 3D RVE simulations were performed and compared to identify the most appropriate boundary conditions for the more time-efficient 2D simulations. The proposed method for extracting phase-specific constitutive behavior was validated by determining phase properties in a range of two-phase materials, including dual phase steel, steel welds, and Al-Ni alloys. This approach provides a means for extracting phase-specific mechanical properties using the microstructure, experimental tensile test data, and phase elastic moduli as input, providing insight into the contributions of individual phases to properties of multi-phase alloys toward new alloy development or microstructure optimization.