Numerical Analysis on the Spatiotemporal Characteristics of the Portevin-Le Chatelier Effect in Ti-12Mo Alloy

A simplified 3D FE model based on McCormick's model is developed to numerically predict the spatiotemporal behaviors of the PLC effect in Ti-12Mo alloy tensile tests at 350 degrees C with strain rates from the order of $10^{-4}$ s$^{-1}$ to $10^{-2}$ s$^{-1}$. The material parameter identification procedure is firstly presented in details, and the simulated results are highly consistent with experimental ones, especially in terms of stress drop magnitudes and PLC band widths. The distribution of simulated stress drop magnitudes at a constant tensile velocity (0.01 mm/s) follows a normal distribution and its peak value is in the range of 26-28 MPa. Furthermore, the simulated band width slightly fluctuates with the increase of true strain and its average value is about 1.5 mm. Besides, the staircase behavior of strain-time curves and the hopping propagation of the PLC band are observed in Ti-12Mo alloy tensile process, which are related to the strain localization and stress drop magnitudes.