Fracture mechanics-based analysis of the fatigue limit of Ti6Al4V alloy specimens manufactured by SLM in as-built surface conditions by means of areal measurements

The fatigue limit of additively manufactured Ti6Al4V alloy specimens in as-built surface conditions is estimated using a fracture mechanics analysis involving different definitions of an effective crack size related to the areal parameter, Sv, of the surface texture, on which the fatigue limit is made to depend. The approach adopts the Extreme Value Statistics (EVS) to determine the largest Sv of the individual as well as the entire batch of specimens and is validated by comparison with the experimental results. Finally, the applicability of the approach by using the 1D roughness profile parameter, Rv, is discussed using the EVS with appropriate hypotheses.