Mechanical and wear properties of ultrafine-grained pure Ti produced by multi-pass equal-channel angular extrusion

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 517; no. 1; pp. 97 - 104
• Main Authors: Purcek, G., Saray, O., Kul, O., Karaman, I., Yapici, G.G., Haouaoui, M., Maier, H.J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 20.08.2009; Elsevier
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equal-channel angular extrusion; Exact sciences and technology; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical behavior; Mechanical properties of solids; Other heat and thermomechanical treatments; Physics; Titanium; Treatment of materials and its effects on microstructure and properties; Tribology and hardness; Ultrafine-grained materials; Wear; Titanium; Ultrafine-grained materials; Mechanical behavior; Equal-channel angular extrusion; Wear; Sliding wear; Ductility; Tribochemical reaction; Wear testing; ECAP; Hardening; Transition elements; Fine grain structure; Microstructure; Tensile properties
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2009.03.054

In this study, pure grade 2 Ti was processed via equal-channel angular extrusion (ECAE) for 8 and 12 passes following route-E at 300 °C. After processing, the microstructural evolution, tensile properties and wear behavior were investigated. ECAE-processed Ti exhibited a significant improvement in strength values with a slight decrease in ductility. However, the wear test results surprisingly showed that the strengthening of titanium by ECAE processing does not lead to the improvement of wear resistance at least for the pressures and sliding distances used in this study. This finding was mainly attributed to the tribochemical reaction leading to oxidative wear with the abrasive effect in Ti. Three distinct regions were formed on the subsurface of CG and UFG Ti after sliding wear, which are the tribolayer including titanium oxide with smeared wear material at the top, a deformed region having material structure oriented along the sliding direction in the middle, and the original unaffected bulk material at the bottom.