Process mapping of laser surface modification of AISI 316L stainless steel for biomedical applications

Abstract

A 1.5-kW CO 2 laser in pulsed mode at 3 kHz was used to investigate the effects of varied laser process parameters and resulting morphology of AISI 316L stainless steel. Irradiance and residence time were varied between 7.9 to 23.6 MW/cm 2 and 50 to 167 µs respectively. A strong correlation between irradiance, residence time, depth of processing and roughness of processed steel was established. The high depth of altered microstructure and increased roughness were linked to higher levels of both irradiance and residence times. Energy fluence and surface temperature models were used to predict levels of melting occurring on the surface through the analysis of roughness and depth of the region processed. Microstructural images captured by the SEM revealed significant grain structure changes at higher irradiances, but due to increased residence times, limited to the laser in use, the hardness values were not improved.

Spinodal decomposition in AISI 316L stainless steel via high-speed laser remelting

“…From the previous studies, it was established that energy densities greater than 6700J/cm 2 resulted in ablation regardless of the residence time [13]. At this energy level sample sparking was observed.…”

“…This present work focused on samples treated at the high irradiance and low residence time; specifically, samples treated at fluences of 950 and 2096J/cm 2 with each sample repeated three times. A detailed study of the effects of processing parameters on melt pool depth and surface roughness is presented elsewhere [13].…”

On the Improvement of AA2024 Wear Properties through the Deposition of a Cold-Sprayed Titanium Coating

“…Marrocco et al (2011) proved that post-deposition laser treatment on titanium coating eliminates the residual micro-porosity and forms a high quality corrosion barrier layer [3]. Other authors studied the laser treatments in order to improve the superficial properties of both coatings and bulk materials [9][10][11]. The authors' previous work showed the optimal process parameters of the laser treatment to obtain a compact titanium dioxide layer on cold-sprayed titanium coating [12].…”

Suppression effect of a steady magnetic field on molten pool during laser remelting

“…The effects of various laser process parameters and associated morphologies of AISI 316L stainless steel have been investigated. The experiment results showed that a combination of low level of irradiance and long time of residence was the best for lower roughness and moderate depth of processing [12]. Although process parameters are usually optimized to improve the surface morphology, in some cases the process parameters not only influence the surface morphology, but also affect other properties of the surface such as wear and corrosion resistance, therefore, these parameters cannot be reasonably optimized in terms of surface morphology solely.…”