High-cycle fatigue behavior in heterostructured materials: a perspective

Heterostructured (HS) materials, composed of distinct soft and hard domains, offer a promising approach to overcome the traditional strength-ductility trade-off via hetero-deformation-induced (HDI) effects. While their static mechanical performance is well-documented, their fatigue behavior remains little explored. This perspective deliberates on a critical stress threshold reported in the fatigue behavior of HS materials. Below it, HS materials follow Basquin’s law, consistent with conventional homogeneous alloys. Above it, HDI-driven interactions, such as stress redistribution, strain delocalization and delayed crack nucleation in soft domains, substantially improve fatigue life. Key microstructural design principles are proposed to optimize fatigue resistance by balancing interfacial areas and soft domain size. This perspective provides insight for designing HS materials for high-cycle fatigue applications.