Experimental investigation and micromechanical modeling of load partitioning behavior of duplex stainless steel 2205 during cyclic hardening

Abstract

This paper aims to understand the load partitioning behavior between austenite and ferrite of duplex stainless steel 2205 under cyclic loading by experiments, including a series of low cycle fatigue tests and electron back scattered diffraction observation. Meanwhile, a crystal plasticity finite element model was developed to predict the cyclic micromechanical response of two constituent phases. The results show that more slip bands were found within the austenite. The cyclic plasticity of 2205 started within the austenite, and gradually translated into the ferrite with the elevation of applied cyclic amplitude. The plastic deformation within the austenite was inclined to form at the phase boundaries, while it promoted at grain boundaries in the ferrite. The micromechanical elasto-viscoplastic parameters of two constituent phases were calibrated accurately. The proposed crystal plasticity finite element model has a great ability of predicting not only the time- and amplitude- macroscopic cyclic hardening behavior but also the micro-deformation within two constituent phases, even the cyclic hardening of 2205 with different phase ratios can also be reproduced accurately. The prediction error on cyclic stress amplitude of 2205 during cyclic hardening can be controlled within 3.2%.