SURFACE MODIFICATION OF LPBF-FABRICATED 316L STAINLESS STEEL USING SHOT PEENING: WETTABILITY AND CORROSION PERFORMANCE FOR BIOMEDICAL IMPLANTS
Mariya Das Gurram, Vishnu Vardhana Naidu B
Abstract: This study investigates the effect of shot peening (SP) processing times of 6 min (SP6), 8 min (SP8), and 10 min (SP10) on the surface wettability and electrochemical corrosion behavior of laser powder bed fusion (LPBF)-fabricated 316L stainless steel (316L SS) for biomedical implant applications. While LPBF allows for complex, customized implant fabrication, as-printed (AP) components suffer from high surface roughness, residual porosity, and tensile residual stresses that compromise corrosion resistance and biocompatibility. To resolve these issues, SP was applied to induce severe plastic deformation and refine the near-surface microstructure. Surface properties and electrochemical performance were evaluated using FESEM, Optical Microscopy, contact angle measurements (in DI water and PBS), potentiodynamic polarization, and electrochemical impedance spectroscopy (in 0.5 M NaCl). SP successfully refined the microstructure, minimized surface defects, and introduced beneficial compressive residual stresses, producing condition-dependent changes in surface wettability. Contact angles ranged from 26.23±1.85° to 75.26±2.78° in DI water and from 73.08±2.84° to 88.60±3.10° in PBS under the treated condition. All investigated surfaces remained hydrophilic, with contact angles below 90°. Furthermore, corrosion resistance improved progressively in the order of SP10 > SP8 > SP6 > AP. The SP10 specimen exhibited the lowest corrosion rate (decreasing from 8.907±1.02 mpy to 2.103±0.55 mpy) and a substantial increase in charge-transfer resistance (10100 Ω·cm²) as indicated by PDP and EIS results. Overall, shot peening improved the surface and corrosion resistance of LPBF 316L stainless steel, with the best conditions depending on the desired performance. More in vitro and long-term studies are needed to confirm its suitability for biomedical implants.
Keywords: Laser Powder Bed Fusion (LPBF); 316L stainless steel; Shot peening; Wettability; Corrosion resistance
DOI: 10.24874/PES08.03.021
Recieved: 13.06.2026 Revised: 16.07.2026 Accepted: 21.08.2026
UDC:
Reads: 15 
