Modeling serrated flow of SS 316L under dynamic strain aging effect

The serrated behavior of the stress-strain curves also known as PLC effect due to dynamic strain aging of SS 316L is investigated here from room temperature to 550 degrees C. Tensile tests were conducted for strain rates 10-5-10-2/s. Serrations of type D, type A and type A+B were observed at different loading conditions. A material model was fitted to the experimental data to simulate the serrated flow in the stress strain diagrams. For this an approach similar to a previous study done with an Al-Mg alloy was followed. However, few changes in the analysis steps were performed to accommodate temperature dependency, a feature not addressed in the earlier work. In addition, the fitment technique was improvised so that the material model could be fit through a substantially smaller set of experimental data, thus improving the speed of the fitting process. Finally, comparisons were done between the experimental data and the results from the simulations. Critical strains from the simulations were found to be of the same order of magnitude of the experimental critical strains and the serrations could also be found in the simulated stress-strain diagrams similar in some aspects to the experimental serrations.