Author(s)

Mitsuru Sato¹, Osamu Takakuwa¹, Masaaki Nakai², Mitsuo Niinomi², Fumio Takeo³, Hitoshi Soyama¹

¹Department of Nanomechanics, Graduate School of Engineering, Tohoku University, Sendai, Japan.
²Institute for Materials Research, Tohoku University, Sendai, Japan.
³Department of Mechanical Engineering, Hachinohe National College of Technology, Hachinohe, Japan.

Although Electron Beam Melting (EBM) is an innovative technology, the fatigue properties of materials manufactured by EBM may be lower than those of casted and wrought materials due to defects and surface roughness. In order to enhance the fatigue life of components or structures manufactured by EBM, a mechanical surface treatment technology, e.g., peening, would be effective because peening introduces high compressive residual stress at the surface which can extend the fatigue life considerably. In the present study, specimens were manufactured by EBM using titanium alloy Ti-6Al-4V powder. Two types of specimens were prepared: as-built and as-machined specimens. Specimens of each type were treated by cavitation peening or shot peening. The fatigue lives of the specimens were evaluated by a plate bending fatigue tester. The residual stress and surface roughness were also evaluated. The results obtained showed that the fatigue strength of as-built specimens can be improved by 21% by cavitation peening or shot peening, and the fatigue life under particular applied stresses can also be extended by 178% by cavitation peening.

Component, Electron Beam Melting, Ti-6Al-4V, Cavitaion Peening, Residual Stress, Fatigue

Sato, M. , Takakuwa, O. , Nakai, M. , Niinomi, M. , Takeo, F. and Soyama, H. (2016) Using Cavitation Peening to Improve the Fatigue Life of Titanium Alloy Ti-6Al-4V Manufactured by Electron Beam Melting. Materials Sciences and Applications, 7, 181-191. doi: 10.4236/msa.2016.74018.