Abstract
The effects of post-ECAP (equal channel angular pressing) annealing on microstructure and high-cycle fatigue behavior of ultrafine-grained (UFG) copper were examined. Grains with sizes up to a few tens of micrometers surrounded by fine grains were formed after the annealing. The fatigue life of post-ECAP annealed samples in the short-and medium-life fields was found to decrease, while in the long-life field in excess of 10^7 cycles, the fatigue strength was slightly increased. The effect of bimodal microstructure on high-cycle fatigue strength is discussed from the viewpoints of microstructural evolution due to cyclic stresses.
