Fatigue Performance of Al7075-T73 and Ti-6Al-4V: Comparing Results after Shot Peening, Laser Shock Peening and Ball-Burnishin

Author:  Mhaede, Sano, Altenberger, Wagner
Source:  Conf Proc 2011: ICSP-11 South Bend, IN USA (pgs. 297-302)
Doc ID:  2011049
Year of Publication:  2011
Abstract:  
Abstract Rotating beam fatigue specimens of the well known high-strength aluminum alloy Al7075 and the titanium alloy Ti-6Al-4V were mechanically surface treated by various methods. Conventional shot peening (SP), ultrasound shot peening (USP), laser shock peening without coating (LPwC) and ball-burnishing (BB) were used and the resulting changes in surface topography, and residual stress-depth profiles were studied. Utilizing the same Almen intensity, USP led to roughness and micro-hardness values in near-surface regions slightly lower than SP, this result being explained by the larger shot size. However, the residual stress-depth profiles after SP and BB were very similar. LPwC and BB led to penetration depths of induced plastic deformation much greater than those observed after USP or SP. On average, micro-hardness values in near-surface regions were somewhat higher in BB compared to LwCP. Among the various mechanical surface treatments, ball-burnishing led to most marked fatigue strength enhancements. Keywords Shot Peening, Ultrasound Shot Peening, Laser shock Peening, Ball-Burnishing, surface layer properties, fatigue performance