A Comparison of Warm and Combined Warm and Low‐Temperature Processing Routes for the Equal‐Channel Angular Pressing of Pure Titanium

• Published in: Advanced engineering materials 2020-02, Vol.22 (2), p.n/a
• Main Authors: Bulutsuz, Asli Günay, Chrominski, Witold, Huang, Yi, Kral, Petr, Yurci, Mehmet Emin, Lewandowska, Malgorzata, Langdon, Terence G.
• Format: Article
• Language: English
• Subjects: commercial purity titanium; equal-channel angular pressing; hardness; processing routes; ultrafine grains
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.201900698

Two different processing routes are used to investigate the microstructure and strength of commercial purity (CP) titanium of grade 4 processed by equal‐channel angular pressing (ECAP). In the combined temperature (CT) route, the specimens are pressed at 723 K in the first pass and at 373 K in the second pass, but in the warm temperature (WT) route, the specimens are pressed through two passes at 723 K. Both routes lead to an inhomogeneous microstructure with an average grain size of ≈1.5 and ≈1.7 μm after the CT and WT routes, respectively. Both routes give improved strengthening and higher hardness, but the CT route with a lower temperature step gives the highest ultimate tensile strength of ≈790 MPa. The inclusion of a lower temperature processing step may be important for optimizing the strength of CP Ti for the use in medical implants. The effect of combined low (373 K) and warm temperature (723 K) route effect on microstructure and mechanical properties are determined for commercial purity (CP) Ti. After two passes, the samples have an inhomogeneous microstructure and hardness distribution. For the lower temperature route, the specimen has the highest strength. The inclusion of a lower temperature processing step is important for optimizing the strength of CP Ti.