Fatigue strength estimation of net-shape L-PBF Co–Cr–Mo alloy via non-destructive surface measurements

Abstract

One of the primary challenges in utilizing additive manufacturing for load-bearing metal components in the aerospace industry lies in the relatively low fatigue strength and significant variability stemming from the typically rough as-built surfaces. The goal of this research is to develop a model able to robustly correlate parameters obtained by non-destructive measurements to the fatigue strength of a generic surface state for a cobalt-chrome alloy manufactured via laser powder bed fusion (L-PBF). The results show that a relatively accurate estimation of fatigue strength of a generic surface quality can be performed via high-quality non-destructive roughness measurements coupled with statistical considerations and fracture mechanics-based assessments. This provides the capability of comparing different surface states and selecting the best option for fatigue strength with limited experimental effort and might prospectively set the basis for qualification of L-PBF components in the presence of rough surfaces.