The influence of recrystallization annealing time on high cycle fatigue behavior of high-Mn austenitic steel at 77 K

Abstract

Three high manganese austenitic steels were prepared by different recrystallization annealing time (0, 32, and 128 min) to investigate the effect of recrystallization annealing time on high-cycle fatigue behavior at 77 K. The microstructure was characterized by means of quasi in situ scanning electron microscope (SEM). When fatigue life is about 5.0 × 106 loading cycles, the fatigue strength at 77 K increases from 512 MPa to 625 MPa with the decrease in recrystallization annealing time (RAT). Decrease in RAT leads to grain refinement and the increase in density of dislocation. Grain refinement can delay crack initiation, prevent crack propagation, and hardly hinders the formation of deformation twins. In addition, it is surprising that the grain refinement and the increase in dislocation density promote the formation of nanoscale voids, which leads to stress relaxation and thus improve the fatigue performance.