A macro-micro approach for identifying crystal plasticity parameters for necking and failure in nickel-based alloy haynes 282

•A two-scales macro-micro method is developed to model the materials undergo necking and failure, in order to determine the material intrinsic properties at microstructural scale.•A macro rate-dependent anisotropic plasticity and damage model is proposed that well captured the necking strain, total elongation and reduction of area at various applied strain rate.•The ‘true’ stress-strain behaviors at the necking zone are identified and transferred to the crystal plasticity microstructural model, which then captures the underlying heterogenous deformation and damage in the microstructure during the necking, and reveals ‘true’ microstructure-properties relationship. This work develops a two-scales macro-micro approach to address the challenge in calibrating crystal plasticity microstructural models when samples undergo necking prior to fracture. The crystal plasticity models are crucial for predicting the materials’ plastic deformation and failure at the microstructure level, identifying the materials’ intrinsic properties as well as investigating the microstructure-properties relationships. However, after necking occurs, the experimentally measured stress-strain curves fail to reflect the materials ‘true’ stress-strain behavior and cannot be directly fitted into crystal plasticity models. The proposed macro-micro approach employs a top-down strategy to address this challenge, which has been studied with experimental tests on precipitation-strengthened Ni-based superalloy Haynes® 282®. In this approach, a macro rate-dependent anisotropic plasticity model with Voce-type hardening and Rice-Tracey damage law is first utilized to model the deformation and failure of the tensile bar, and calibrated by matching the stress-strain curves, necking strain, and reduction of area. Especially, to match the testing results under different applied strain rates, the rate-sensitivity parameter m and saturation stress in the elasticity model are modified to incorporate dependence on the local strain rate. Then, the ‘true’ stress-strain behaviors are extracted from the necking zone of the macro-model, which are used to calibrate a micro-model with explicit microstructures and governed by an extended crystal plasticity law. The consistency between the micro-model and macro-model are enforced during calibration. The calibration outcomes from the crystal plasticity model elucidate the materials intrinsic properties for slip, hardening, and failure, which is vital for further inves