Modeling cyclic plasticity of additively manufactured alloy Mar-M-509 using a high-performance spectral-based micromechanical model

Abstract

A high-performance full-field spectral crystal plasticity model referred to as MPI-ACC-EVPCUFFT is adapted to study the deformation behavior of additively manufactured Mar-M-509® cobalt-based superalloy. The model features a dislocation density-based hardening law for the evolution of slip resistance, a barrier effect induced by grain morphology to influence the slip resistance, and a slip system-level back-stress law for adjusting the driving force to slip. The model is used to interpret and predict strength of the alloy in tension, compression, load reversal, and low-cycle fatigue as a function of initial microstructure. The initial microstructure varied from sample-to-sample to represent the effects of build orientation and heat treatment. Results show that the model successfully reproduces phenomena pertaining to monotonic and cyclic deformation including the non-linear unloading, Bauschinger effect, and cyclic hardening/softening using a single set of model parameters. Moreover, the model offers insights into fluctuations of mechanical fields and strain partitioning.

Keywords

• Microstructures
• Dislocation density
• Crystal plasticity
• Additive manufacturing
• Mar-M-509