Shape memory characteristics of a nanocrystalline TiNi alloy processed by HPT followed by post-deformation annealing
Authors: Shahmir, H., Nili-Ahmadabadi, M., Huang, Y., Jung, J.M., Kim, H.S. and Langdon, T.G.
Journal: Materials Science and Engineering: A
Volume: 734
Pages: 445-452
ISSN: 0921-5093
DOI: 10.1016/j.msea.2018.08.019
Abstract:A martensitic TiNi shape memory alloy was processed by high-pressure torsion (HPT) for 1.5, 10 and 20 turns followed by post-deformation annealing (PDA) at 673 and 773 K for various times in order to study the microstructural evolution during annealing and the shape memory effect (SME). Processing by HPT followed by the optimum PDA leads to an appropriate microstructure for the occurrence of a superior SME which is attributed to the strengthening of the martensitic matrix and grain refinement. A fully martensitic structure (B19’ phase) with a very small grain size is ideal for the optimum SME. The results indicate that the nanocrystalline microstructures after PDA contain a martensitic B19’ phase together with an R-phase and this latter phase diminishes the SME. Applying a higher annealing temperature or longer annealing time may remove the R-phase but also reduce the SME due to grain growth and the consequent decrease in the strength of the material. The results show the optimum procedure is a short-term anneal for 10 min at 673 K or only 1.5 min at 773 K after 1.5 turns of HPT processing to produce a maximum recovered strain of ~8.4% which shows more than 50% improvement compared with the solution-annealed condition.
https://eprints.bournemouth.ac.uk/31196/
Source: Scopus
Shape memory characteristics of a nanocrystalline TiNi alloy processed by HPT followed by post-deformation annealing
Authors: Shahmir, H., Nili-Ahmadabadi, M., Huang, Y., Jung, J.M., Kim, H.S. and Langdon, T.G.
Journal: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Volume: 734
Pages: 445-452
eISSN: 1873-4936
ISSN: 0921-5093
DOI: 10.1016/j.msea.2018.08.019
https://eprints.bournemouth.ac.uk/31196/
Source: Web of Science (Lite)
Shape memory characteristics of a nanocrystalline TiNi alloy processed by HPT followed by post-deformation annealing
Authors: Shahmir, H., Nili-Ahmadabadi, M., Huang, Y., Jung, J.M., Kim, H.S. and Langdon, T.G.
Journal: Materials Science and Engineering A
Volume: 734
Pages: 445-452
ISSN: 0921-5093
DOI: 10.1016/j.msea.2018.08.019
Abstract:© 2018 Elsevier B.V. A martensitic TiNi shape memory alloy was processed by high-pressure torsion (HPT) for 1.5, 10 and 20 turns followed by post-deformation annealing (PDA) at 673 and 773 K for various times in order to study the microstructural evolution during annealing and the shape memory effect (SME). Processing by HPT followed by the optimum PDA leads to an appropriate microstructure for the occurrence of a superior SME which is attributed to the strengthening of the martensitic matrix and grain refinement. A fully martensitic structure (B19’ phase) with a very small grain size is ideal for the optimum SME. The results indicate that the nanocrystalline microstructures after PDA contain a martensitic B19’ phase together with an R-phase and this latter phase diminishes the SME. Applying a higher annealing temperature or longer annealing time may remove the R-phase but also reduce the SME due to grain growth and the consequent decrease in the strength of the material. The results show the optimum procedure is a short-term anneal for 10 min at 673 K or only 1.5 min at 773 K after 1.5 turns of HPT processing to produce a maximum recovered strain of ~8.4% which shows more than 50% improvement compared with the solution-annealed condition.
https://eprints.bournemouth.ac.uk/31196/
Source: Manual
Preferred by: Yi Huang
Shape memory characteristics of a nanocrystalline TiNi alloy processed by HPT followed by post-deformation annealing
Authors: Shahmir, H., Nili-Ahmadabadi, M., Huang, Y., Jung, J.M., Kim, H.S. and Langdon, T.G.
Journal: Materials Science and Engineering: A
Volume: 734
Issue: September
Pages: 445-452
ISSN: 0921-5093
Abstract:A martensitic TiNi shape memory alloy was processed by high-pressure torsion (HPT) for 1.5, 10 and 20 turns followed by post-deformation annealing (PDA) at 673 and 773 K for various times in order to study the microstructural evolution during annealing and the shape memory effect (SME). Processing by HPT followed by the optimum PDA leads to an appropriate microstructure for the occurrence of a superior SME which is attributed to the strengthening of the martensitic matrix and grain refinement. A fully martensitic structure (B19’ phase) with a very small grain size is ideal for the optimum SME. The results indicate that the nanocrystalline microstructures after PDA contain a martensitic B19’ phase together with an R-phase and this latter phase diminishes the SME. Applying a higher annealing temperature or longer annealing time may remove the R-phase but also reduce the SME due to grain growth and the consequent decrease in the strength of the material. The results show the optimum procedure is a short-term anneal for 10 min at 673 K or only 1.5 min at 773 K after 1.5 turns of HPT processing to produce a maximum recovered strain of ~8.4% which shows more than 50% improvement compared with the solution-annealed condition.
https://eprints.bournemouth.ac.uk/31196/
Source: BURO EPrints