Ratcheting assessment of additively manufactured SS316 alloys at elevated temperatures within the dynamic strain aging domain

The present study has evaluated the accumulation of plastic strain in additively manufactured (AM) stainless steel 316 samples undergoing asymmetric loading cycles at elevated temperature range where the dynamic strain aging (DSA) phenomenon occurred. The ratcheting response of AM steel samples were assessed through the use of the combined isotropic-kinematic hardening framework. The dynamic strain aging was introduced into the dynamic recovery term of the Ahmadzadeh-Varvani (A-V) kinematic hardening rule by an exponential function ψ( p, T ). This function enabled the hardening framework to evaluate the ratcheting of AM steel samples at operating temperatures within the DSA domain. The DSA temperature range for AM SS316 samples fell between 700 K to 1140 K. Within this temperature domain, the interaction between solute atoms and dislocations led to an increase in material strength and suppressed the magnitude of ratcheting over the loading cycles. The influence of DSA on the backstress evolution and the yield surfaces translated in the deviatoric stress space and their subsequent influence on the ratcheting of samples using the A-V model were further discussed. The predicted ratcheting curves at the DSA temperature domain were found in close agreement with those of measured values.