Chin, K.S., Idapalapati, S. & Ardi, D.T. J. of Materi Eng and Perform (2019). https://doi.org/10.1007/s11665-019-04468-3
Nickel-based superalloy IN718 specimens were subjected to two surface treatments, namely shot peening (SP) and deep cold rolling (DCR) to investigate the effects of surface integrity (in particular residual stresses and cold work) on fatigue performance. Residual stress and cold work profiles of the different specimens were obtained using x-ray diffraction (XRD). Microhardness profiles were also obtained from the samples as a comparison against full width at half maximum (FWHM) from XRD in evaluation of cold work. Surface roughness effects were found to be insignificant, evident from the surface-initiated fatigue cracks in both SP and DCR specimens. Fatigue life improvements exhibited by SP and DCR specimens over the as-machined equivalent can be attributed to crack retardation due to work-hardened layer as well as compressive residual stresses.