A Comparison of Surface and Sub-surface Features Induced by Shot Peening vs. Laser Peening on a Duplex Aged Beta Ti Alloy

Abstract

The paper presents a study of the surface and subsurface characteristics induced by laser peening without coating (LPwC) and dual shot peening (DSP) on the duplex aged Ti-15 V-3Al-3Cr-3Sn alloy. In 3D-optical topography analysis, DSP resulted in a six-fold enhancement in the surface roughness (Sa). Whereas, LPwC resulted in unaltered surface roughness (Sa) compared to the polished/unpeened sample. In cross-sectional microstructure studies, deformed grains and heat affected zones were observed in the near surface region of shot peened, and laser peened samples respectively. Moreover, compared to bulk hardness, shot peening and laser peening has resulted in maximum increment of ~28% and ~12% in microhardness of the near peened surface region respectively.