Microstructure and tribological response of selective laser melted AISI 316L stainless steel: the role of severe surface deformation

Vikesh Kumar, Manoj D. Joshi, Catalin Pruncu, Indrasen Singh, Santosh S. Hosmani

Research output: Contribution to journalArticlepeer-review

Abstract

This study investigates the effect of surface mechanical attrition treatment (SMAT) (a severe surface-deformation process) on microstructure and tribological behavior of AISI 316L steel samples manufactured using the selective laser melting (SLM) technique. The specimens are built in different directions (0°, 45°, and 90°). The microstructure of annealed SLM samples shows the non-uniform distribution and random orientation of grains. It contains high-angle grain boundaries and a high density of dislocations. The average grain size is about 63, 51, and 41 μm for 0°, 45°, and 90° build direction, respectively. SMAT is beneficial for SLM steel to reduce surface roughness (by ~ 87%) and eliminate internal porosity. The deformed layer of SLM steel shows a highly dense network of slip bands, distortion of grains, and hardness gradient (up to the depth of about 600 μm). Increase in surface hardness due to SMAT is maximum (~ 54%) for the sample having 90° build direction. Typical observation of deformation-induced martensite is absent for the SMAT-processed SLM steel. Under the higher load (especially, 20 N), the tribological response of sample manufactured in the 90° direction is superior amongst the non-treated samples. Severe surface deformation enhances the wear resistance and reduces the COF of SLM steel.
Original languageEnglish
JournalJournal of Materials Engineering and Performance
Early online date12 Apr 2021
DOIs
Publication statusE-pub ahead of print - 12 Apr 2021

Keywords

  • surface mechanical attrition treatment (SMAT)
  • materials engineering
  • tribology
  • AISI 316L steel
  • surface-deformation processes
  • surface nanostructuring

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