Ultrahigh fatigue resistance enabled by heterostructural design

Enhancing the fatigue resistance of metals remains a significant challenge in materials engineering. This study demonstrates that titanium exhibits remarkable fatigue resistance when heterostructures are introduced via additive manufacturing. Compared to homogeneously structured titanium, heterostructured titanium shows a remarkable 141% improvement in fatigue strength and a 53% enhancement in fatigue ratio. The heterostructure promotes the formation of high-density geometrically necessary dislocations, leading to hetero-deformation-induced strengthening under cyclic loading. This process enhances structural stability, suppressing fatigue crack initiation and propagation, thus improving fatigue resistance. These findings suggest that heterogeneity is a promising strategy for enhancing fatigue resistance across various alloy systems.