Coverage and Peening Angle Effects in Shot Peening on HCF Performance of Ti-6Al-4V

Author:  A. Jochen P. Fuhr1 B. Mahmoud Basha2, C. Manfred Wollmann2, D. Lothar Wagner2 1 Curtiss-Wright Surface Technologies/Metal Improvement Company, Germany 2 Institute of Materials Science and Engineering, TU Clausthal, Germany
Source:  ICSP14 Milan
Doc ID:  2022047
Year of Publication:  2022
Abstract:  
Shot peening of titanium alloys is known to enhance the HCF performance by inducing in near-surface regions residual compressive stresses and increasing the dislocation density. The present work aimed at studying the effect of coverage and peening angle effects in shot peening on cyclic fatigue performance on Ti-6Al-4V. For shot peening a soft and hard type of cast steel shot and a comparable size conditioned cut wire shot have been used. The coverage was varied from 20 % to 1200 % and the peening angle from 90 to 30°. Fatigue performance of shot peened rotating- and alternating-bending fatigue specimens was studied. The results indicate that low (20%) coverage peening leads to a loss whereas full (100 %) up to a high (1200 %) coverage was found to result in a marked increase in HCF strength. The variation of peening angles resulted in a significant beneficial effect on the fatigue performance in direction to increasingly flat angles and high coverages (1200 %) at constant Almen intensities of 0,20 mmA. These results are even more interesting as those peened surfaces resulted in the highest surface roughness and a topography with a starting waviness.