Hot deformation behavior and microstructural evolution of a modified 310 austenitic steel

• Precipitates facilitate the nucleation of DRX grain, but inhibit growth of them.
• Some coarse precipitates change the deformation texture in the matrix.
• DRX make that LAGBs decrease while twin GBs and random HAGBs increase gradually.
• Dynamic recrystallization occurs more easily at high temperature or strain rate.

To study the hot deformation behavior and microstructural evolution of a new modified 310 austenitic steel, hot compression tests were conducted at the temperature range from 800 to 1100 °C with strain rate of 0.1–10 s−1 and strain of 30–70% using Gleeble 3500 thermal–mechanical simulator. The results showed that the serrated flow curves were caused by the competitive interaction between solute atoms and mobile dislocations. There were some coarsened precipitates on the high angle grain boundaries (HAGBs), which facilitated the nucleation of dynamic recrystallization grains. But these precipitates inhibited the growth of the recrystallization grains, and changed the deformation texture in the matrix. Low angle grain boundaries (LAGBs) decreased, while twin GBs and random HAGBs and increased as dynamic recrystallization occurred. Dynamic recrystallization occurred more readily at evaluated temperature or high strain rate. The true stress decreased with the reduction of LAGBs percent. The internal connections between mechanics and microstructures were also discussed.