Study on strain distribution and texture evolution of Fe-0.18C-4Al-7Mn steel under different strain rate conditions

The objective of this study is to examine the effect of strain rate on the distribution of strain and evolution of texture components in thermomechanically processed intercritically annealed (at 750 degrees C for 1 hr.) Fe-0.18C-4Al7Mn (wt.%) steel. Room temperature tensile tests are performed on the annealed sample at strain rates of 1.33 x 10-4, 6.65 x 10-4 and 13.3 x 10-4 s-1. The electron backscatter diffraction (EBSD) analysis reveals that there is a notable decrease in the fraction of low-angle grain boundaries (LAGBs) from 85 to 28 % as the strain rate is increased from 1.33 x 10-4 to 13.3 x 10-4 s-1. The sample, subjected to a strain rate of 1.33 x 10-4 s-1, exhibits the highest fraction of deformed grains and the lowest fraction of recrystallized grains. As the strain rate increases, the higher fraction of recrystallized grain remains undeformed, leading to lower strain intensity. The transformation-induced plasticity (TRIP) effect induces a higher transformation ratio of austenite to martensite at low strain rates. An intense alpha-fiber with strong components, primarily Ms Brass, Goss/Brass twin, and Goss is observed at low strain rates.