A critical examination of pure tantalum processed by high-pressure torsion

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

卷:638

Article

Maury, Nicolas¹  Zhang, Nian Xian²  Huang, Yi²  Zhilyaev, Alexander P.^3,4  Langdon, Terence G.^2,5,6 

[1] INPT, ENSIACET, F-31077 Toulouse 04, France

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

[3] Russian Acad Sci, Inst Met Supeiplast Problems, Ufa 450001, Russia

[4] St Petersburg State Polytech Univ, Res Lab Mech New Nanomat, St Petersburg 195251, Russia

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

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

关键词: Electron backscatter diffraction;    Hardness;    High-pressure torsion;    Tantalum;    Ultrafine grains;   

DOI  :  10.1016/j.msea.2015.04.053

来源: Elsevier

【 摘 要 】

Tantalum, a common refractory metal with body-centred cubic (BCC) crystalline structure, was processed by high-pressure torsion (HPT) at room temperature through different numbers of rotations. Significant grain refinement and high strength were achieved with a reduction in grain size from similar to 60 mu m to similar to 160 nm and an increase in strength from similar to 200 to > 1300 MPa. Hardness measurements revealed a high level of homogeneity after 10 turns of HPT but the hardness after 10 turns was slightly lower than after 5 turns indicating the occurrence of some recovery. Tensile testing at a strain rate of 1.0 x 10(-3) s(-1) gave high strengths of similar to 1200 MPa but little or no ductility after processing through 1, 5 and 10 turns. The introduction of a short-term (15 min) anneal immediately after HPT processing led to significant ductility in all samples and a reasonable level of strength at similar to 800 MPa. (C) 2015 Elsevier B.V. All rights reserved.

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