Surface and Tribological Properties of Powder Metallurgical Cp-Ti Titanium Alloy Modified by Shot Peening
COATINGS, vol.13, no.1, 2023 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 13 Issue: 1
- Publication Date: 2023
- Doi Number: 10.3390/coatings13010089
- Journal Name: COATINGS
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Applied Science & Technology Source, Communication Abstracts, INSPEC, Metadex, Directory of Open Access Journals, Civil Engineering Abstracts
- Keywords: friction, hardness mapping, implants, shot peening, titanium alloys, topography, wear rate, WEAR BEHAVIOR, MICROSTRUCTURE
- Open Archive Collection: AVESIS Open Access Collection
- Kocaeli University Affiliated: Yes
Abstract
The present study reveals for the first time the dry sliding wear behavior of a powder metallurgical pure titanium alloy (Cp-Ti) modified by shot peening. Cp-Ti samples were manufactured via powder metallurgy, and then their surface and subsurface features were modified using a custom-made, fully automated shot-peening system. The texture isotropy rate and the highest orientation angle of the shot-peened samples were 71.5% and 36 degrees, respectively. The Abbott curves of the shot-peened surfaces revealed that the most common areal roughness value was 5.177 mu m, with a frequency of 8.1%. Shot-peened surfaces exhibited an similar to 20% lower wear rate than unpeened surfaces under dry sliding wear, whereas the coefficient of friction was the same for both surfaces. Micro-ploughing, micro-cutting, oxidation, and three-body abrasion wear mechanisms were observed on the shot-peened and unpeened surfaces. High resolution 3D surface topographies of worn unpeened and shot-peened surfaces revealed micro-scratches and inhomogeneities along wear tracks, which are indicative of three-body abrasion mechanisms during contact. In addition, vertical and horizontal microcracks were visible just beneath the wear track, suggesting a clear indication of plastic deformation during contact. The cross-sectional hardness maps of shot-peened samples revealed the formation of a work-hardened surface layer with shot peening, which improved the wear resistance. These findings support that shot peening can be a useful tool to modify the surface and tribological properties of powder metallurgical Cp-Ti alloys.