A critical examination of pure tantalum processed by high-pressure torsion
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 ?60 ?m to...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
2015-04-27.
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| Subjects: | |
| Online Access: | Get fulltext |
| Summary: | 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 ?60 ?m to ?160 nm and an increase in strength from ?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 1.0×10?3 s?1 gave high strengths of ?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 ?800 MPa. |
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