形变热处理变形量对Fe-25Mn-8Al-5Ni-1.2C 钢组织和性能的影响

The effects of different deformation in thermo-mechanical controlled processing (TMCP) combined the solid solution at 1 050 °C with hot rolling on the microstructure and mechanical properties of Fe-25Mn-8Al-5Ni-1. 2C low-density steels aged at 450 °C were studied by OM, SEM, TEM characterization and other experimental methods. The results show that after TMCP with different rolling reductions and aging, all the tested steels show single-phase austenite grains. With the deformation increasing from 20% to 60%, the grains are refined effectively and the average grain size decreases from 75)um to 14]um, the precipitation and size of B2 increase; the number of the relatively large K carbides are reduced while the smaller are increased, and its distribution gradually became homogenized. Compared with the undeformed aged steel, the yield strength of the aged steels after TMCP increases by 45% — 72% due to the combination of grain refinement strengthening, dislocation strengthening and precipitation strengthening. Meanwhile, the strain hardening ability is improved with the deformation increasing.