Assessment of microstructural effects on the fatigue sensitivity of WC-Co cemented carbides by using microdimples shaped by laser ablation

The residual fracture and fatigue strength/life of two fine-grained WC-Co cemented carbides with different metallic binder content were evaluated by laser-shaping microdimples in samples later tested to failure. Values of residual strength determined under monotonic loading were lower, but less-dispersed, than those measured for pristine samples. They were then used as a baseline for assessing fatigue strength and sensitivity within the finite fatigue life regime. It was found that the grade with higher metal binder content exhibited higher residual strengths, independent of loading mode. Meanwhile, the one with lower metal binder content showed less susceptibility to strength degradation under fatigue. Fractographic analysis confirmed that failures consistently originated from the laser-shaped microdimples, with fracture mechanisms similar to those usually reported for pristine specimens at both meso- and micro-length scales. These results highlight the potential of laser ablation as an effective tool for evaluating microstructural effects on fatigue sensitivity for cemented carbides.