Low-cycle fatigue properties of ultrafine-grained Cu: Influence of grain morphology

This paper investigated the low cycle fatigue properties of ultrafine-grained Cu with equiaxed or lamellar grains. Although the lamellar grained structure shows higher cyclic softening than the equiaxed one, it exhibits a lowcyclic fatigue life improvement. This contradictory can be explained by the homogeneously distributed cyclic damage in the lamellar grained structure which presents a rotational dynamic recrystallization-led grain refinement and the significant intersecting shear bands during low cyclic fatigue. Simultaneously, plenty of secondary cracks in lamellar grained structure further retard the crack propagation by decreasing the stress concentration at the tip of main crack. The results manifest that the grain morphology is an important microstructural parameter controlling the low cyclic fatigue performance.

Automated summary

This paper investigated the low cycle fatigue properties of ultrafine-grained Cu with equiaxed or lamellar grains. Although the lamellar grained structure shows higher cyclic softening than the equiaxed one, it exhibits a lowcyclic fatigue life improvement. This contradictory can be explained by the homogeneously distributed cyclic damage in the lamellar grained structure which presents a rotational dynamic recrystallization-led grain refinement and the significant intersecting shear bands during low cyclic fatigue.