Constitutive flow behavior of IFAC-1 austenitic stainless steel depicting strain saturation over a wide range of strain rates and temperatures

摘要

In this work, model D8A, a thermo-viscoplastic constitutive model is proposed to describe the flow saturation at higher level of strain over a wide range of strain rates and temperatures. Towards this end, isothermal constant true strain rate compression tests were carried out in a temperature range of 1173-1473 K and strain rate range of 0.01-100 s~(-1) on IFAC-1 austenitic stainless steel (SS). Effect of strain, strain rate and temperature on compressive flow behavior of IFAC-1 SS was studied, and IFAC-I SS exhibited flow saturation after strain hardening. Modified Zerilli-Armstrong (MZA) model was employed to describe the flow behavior of this steel in the above mentioned strain rate and temperature domain. However, MZA model was inadequate to provide good description of saturating flow behavior of the alloy IFAC-1. Therefore, model D8A was proposed by improvising the MZA model. D8A contains eight material constants and could describe the flow behavior of IFAC-1 in the entire domain with an average absolute error of 4.5%.