Influence of laser polishing in an inert atmosphere on the high cycle fatigue strength of AISI 1045 steel

Laser polishing of 3D printed mesoscale components

“…Despite roughness of the laser polished structures being within 400 to 600 nm Ra, the surfaces were still found to be short of optical quality standards. Avilés et al [13,14] assessed the surface integrity and fatigue strength of laser polished AISI 1045 steel specimens performed under atmospheric and N2 gas environments. A heat affected zone (HAZ) up to a depth of 100-150 µm beneath the workpiece surface was evident in both cases but with differences in the surface/subsurface characteristics.…”

“…In particular, the formation of oxide layers, micro-cracks and inclusions were observed after laser polishing under normal atmospheric condition while a pearlitic to martensitic transformation together with compressive residual stresses up to 200 MPa in the HAZ was apparent when operating in a N2 environment. Furthermore, the fatigue strength of samples processed under an inert gas condition was ~7.5% higher than those polished in air [14]. The performance of diode-pumped solid-state and CO2 lasers in continuous (CW) mode for LP of DIN 1.2379 (AISI D2) tool steel was evaluated by Ukar et al [15], who also developed a mathematical model to predict the resulting surface roughness [16].…”

A Review of Damage, Void Evolution, and Fatigue Life Prediction Models

“…These unwanted surface features can be reduced by performing the laser polishing in a N2 atmosphere (LPN). Avilés et al [150] studied the high-cycle fatigue behavior of normalized 1045 AISI steel after laser polishing in a N2 atmosphere. The fatigue test results showed that LP improves the HCF fatigue strength of the base material if its average surface roughness of the base material before LP is larger than 0.35 µm.…”

Surface Residual Stress Release Behavior of Shot-Peened Springs

“…Shun Yang et al [12] divided the total life of a material into two parts, the residual stress anti-fatigue life and the material fatigue life, and established a residual stress attenuation law model for the uniaxial stress cycle. Alexander Avilés et al [15] carried out a rotating bending fatigue test on mirrorpolished and shot-peened specimens and put forward a residual stress influence coefficient composed of surface roughness and mechanical properties (residual stress, cold work hardening, hardness, and grain size). Jong-Cheon Kim et al [16] analyzed the relaxation and redistribution of compressive residual stresses (CRSs) during bending fatigue for 0.45% (annealed) carbon steel treated via shot peening under low-cycle fatigue (LCF) and highcycle fatigue (HCF) testing.…”