Fine-grained TWIP steel prepared by powder metallurgy

Abstract Five fine-grained TWIP steels are produced by powder metallurgy. With increasing milling time of the mixed powder, the grain size of the sintered bulk samples decreases from 11.9 μm to 2.9 μm. The grain size refinement can be primarily attributed to a reduction in particle size, a higher degree of alloying and dislocation accumulation in the blend powder. All bulk samples consist of equiaxed grains with many annealing twins, a few stacking faults and nanoscale dispersed particles. With decreasing grain size, the compressive yield strength of the bulk sample increases to 411 MPa, while the yield stress increases significantly but the plasticity gradually declines. As with conventionally cast TWIP steels, the mechanical properties show a typical grain size dependence.