Surface topography analysis based on fatigue fractures obtained with bending of the 2017A-T4 alloy

This work deals with the post-failure analysis of the fatigued fracture in the context of surface topography parameters. The influence of material isotropy on fatigue fractures using metrological methods is presented. The study was carried out on fracture surfaces of different maximum stress at the notch root σmax and stress ratio R. Surface topography and fracture measurements were made using the Infinite Focus technique with the use of the changing the focus, which allowed the collection of data sets. The analysis of the geometric product specification was performed by means of height parameters according to ISO 25178, fractal dimensions as well as surface isotropy. Paper presents that higher values of skewness were received for the stress ratios R = −1, −0.5 than for R = 0, while lower kurtosis values for the stress ratios R = −1 and −0.5 than for R = 0 were observed.