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Original title:
Influence of Heat Treatment on Microstructure and Transformation Characteristics of NiTi Shape Memory Wires
Authors: Zálešák, Jakub ; Kuběnová, Monika ; Čermák, Jiří ; Svoboda, Milan ; Dlouhý, Antonín
Document type: Papers
Conference/Event: METAL 2011 /20./, Brno (CZ), 2011-05-18 / 2011-05-20
Year: 2011
Language: eng
Abstract: The present study shows how heat treatments affect microstructure and transformation behaviour of superelastic Ni-rich NiTi shape memory wires. Wire samples were sealed into quartz tubes, filled with hydrogen reduction atmosphere, heated for 10 minutes at temperatures increasing in a range from 500 to 600°C and subsequently quenched into cold water. Characteristic transformation temperatures MS, MF, AS, AF, thermal hysteresis and latent heats were investigated using differential scanning calorimetry (DSC). We observed significant changes in DSC charts which recorded B2 → R and R → B19‘ phase martensitic transformations. Increasing temperature of the heat treatment resulted in a convergence of the two transformation peaks. R-transformation commenced at systematically lower temperatures and the beginning of the B19‘ transformation was shifted to higher temperatures with increasing temperature of the heat treatment. In parallel, latent heat of the overall B2 → B19‘ transformation clearly increases. We rationalize these significant changes in the transformation behaviour on the basis of the microstructural development during the heat treatment which is characterized by means of SEM, TEM and EBSD techniques.
Keywords: Ni-rich NiTi shape memory alloys; phase transformation temperatures; Superelastic wires
Project no.: CEZ:AV0Z20410507 (CEP), GA106/09/1913 (CEP)
Funding provider: GA ČR
Host item entry: METAL 2011 Conference Proceedings, ISBN 978-80-87294-22-2
Institution: Institute of Physics of Materials AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0006936
Permalink: http://www.nusl.cz/ntk/nusl-110451
The record appears in these collections:
Research > Institutes ASCR > Institute of Physics of Materials
Conference materials > Papers
Authors: Zálešák, Jakub ; Kuběnová, Monika ; Čermák, Jiří ; Svoboda, Milan ; Dlouhý, Antonín
Document type: Papers
Conference/Event: METAL 2011 /20./, Brno (CZ), 2011-05-18 / 2011-05-20
Year: 2011
Language: eng
Abstract: The present study shows how heat treatments affect microstructure and transformation behaviour of superelastic Ni-rich NiTi shape memory wires. Wire samples were sealed into quartz tubes, filled with hydrogen reduction atmosphere, heated for 10 minutes at temperatures increasing in a range from 500 to 600°C and subsequently quenched into cold water. Characteristic transformation temperatures MS, MF, AS, AF, thermal hysteresis and latent heats were investigated using differential scanning calorimetry (DSC). We observed significant changes in DSC charts which recorded B2 → R and R → B19‘ phase martensitic transformations. Increasing temperature of the heat treatment resulted in a convergence of the two transformation peaks. R-transformation commenced at systematically lower temperatures and the beginning of the B19‘ transformation was shifted to higher temperatures with increasing temperature of the heat treatment. In parallel, latent heat of the overall B2 → B19‘ transformation clearly increases. We rationalize these significant changes in the transformation behaviour on the basis of the microstructural development during the heat treatment which is characterized by means of SEM, TEM and EBSD techniques.
Keywords: Ni-rich NiTi shape memory alloys; phase transformation temperatures; Superelastic wires
Project no.: CEZ:AV0Z20410507 (CEP), GA106/09/1913 (CEP)
Funding provider: GA ČR
Host item entry: METAL 2011 Conference Proceedings, ISBN 978-80-87294-22-2
Institution: Institute of Physics of Materials AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0006936
Permalink: http://www.nusl.cz/ntk/nusl-110451
The record appears in these collections:
Research > Institutes ASCR > Institute of Physics of Materials
Conference materials > Papers
Record created 2012-04-03, last modified 2024-01-26