Characteristics of the allotropic phase transformation in titanium processed by high-pressure torsion using different rotation speeds

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:667

Article

Shahmir, Harried¹  Langdon, Terence G.^1,2,3 

[1] Univ Southampton, Fac Engn & Environm, Mat Res Grp, Southampton SO17 1BJ, Hants, England

[2] Univ So Calif, Dept Aerosp & Mech Engn, Los Angeles, CA 90089 USA

[3] Univ So Calif, Dept Mat Sci, Los Angeles, CA 90089 USA

关键词: High-pressure torsion;    Nanostructured materials;    Phase transformations;    Severe plastic deformation;    Titanium;   

DOI  :  10.1016/j.msea.2016.05.001

来源: Elsevier

【 摘 要 】

An investigation was initiated to examine the effect of rotation speed on the allotropic alpha to omega-phase transformation in titanium. A grade 2 commercial purity titanium was processed by high-pressure torsion (HPT) at room temperature up to a maximum of 10 turns using a pressure of 5.0 GPa and different rotation speeds from 0.5 to 2 rpm. It is shown that the allotropic phase transformation occurs during HPT at different rotation speeds but the volume fraction of the omega-phase decreases when the rotation speed is increased. The results indicate that the hardness and strength are decreased by processing the specimens at higher rotation speeds. Additional annealing for 15 min at 423 and 473 K after HPT processing is also effective in changing the volume fractions of the omega-phase and producing an omega to alpha reverse phase transformation. The results are interpreted in terms of the temperature rise during HPT processing. (c) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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