Surface Roughness Based Characterization of Slip Band for Damage Initiation in a Nickel Base Superalloy

This work presents a computational protocol, based on a variance analysis integrated with the bootstrap method, to investigate surface damage resulting from localization of plastic deformation in slip bands of a Ni-base superalloy. For assessment of fatigue crack initiation, surface roughness is introduced to quantify the degree of slip irreversibility. The contribution of this study is to provide a most relevant roughness parameter that can extract the salient features of slip bands within damaged grains, and thus enabling the discrimination of damaged and undamaged grains for description of fatigue-induced surface damage. Results suggest that the maximum peak height ( S p ) is the most relevant parameter. And a very pronounced variability of S p values is observed for damaged grains