Effect of Ageing Temperature on the Microstructures and Mechanical Properties of Ti-Nb Shape Memory Alloys

Abstract:

In this study, Ti-30at.%Nb was subjected to solution annealing at 900°C followed by ageing at 300^o, 400°C, 500°C and 600°C for one hour in order to investigate the effect of ageing temperature on the microstructures and mechanical properties behaviour. It was found that the microstructures of the sample in solution anneal consists of β austenite phase. This indicates that the transformation temperature, Ms, of the material is below room temperatures. The presence of other phases such as α phase and ω precipitates has been detected on the samples after ageing at 500°C and 600°C. Maximum hardness value and tensile strength obtained on the sample aged at 500°C was associated with the presence of ω phase, however the existence of α phase in the sample aged at 600°C provides the lowest hardness and tensile strength. The solution treated sample shows the best shape memory behaviour compared to other heat treated alloys. However, the best superelastic behaviour was observed on the sample aged at 300°C.

• Periodical: Advanced Materials Research (Volume 1024)
• Pages: 304-307
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1024.304
• Online since: August 2014
• Authors: Esah Hamzah*, Kurnia Hastuti, Jasmi Hashim
• Keywords: Ni-Free Alloy, Shape Memory Alloy (SMA), Superelastic Behaviour

References

[1] S. Miyazaki, H.Y. Kim, H. Hosoda, Development and characterization of Ni-free Ti-base shape memory and superelastic alloys, Mater. Sci. Eng. A 438-440 (2006) 18-24.

DOI: 10.1016/j.msea.2006.02.054

[2] M. Brojan, D. Bombac, F. Kosel, T. Videnic, Shape memory alloys in medicine, Mater. Geoenvirontment 55 2 (2008) 173-189.

[3] S. Bartakova, P. Pracha, J. Kudrman, V. Brezina, B. Podhorna, P. Cernochova, J. Vanek, J. Strecha, New Titanium β-alloys for dental implantology and their laboratory-based assays of biocompatibility, Scripta Medica 82 2 (2009) 76-82.

[4] H. Tobe, H.Y. Kim, T. Inamura, H. Hosoda, T.H. Nam, S. Miyazaki, Effect of Nb content on deformation behavior and shape memory properties of Ti–Nb alloys, J. Alloys Compounds 577S (2013) S435–S438.

DOI: 10.1016/j.jallcom.2012.02.023

[5] Y. W. Chai, H.Y. Kim, H. Hosoda, S. Miyazaki, Interfacial defects in Ti–Nb shape memory alloys, Acta Materialia 56 (2008) 3088-3097.

DOI: 10.1016/j.actamat.2008.02.045

[6] Y. Guo, K. Georgarakis, Y. Yokoyama, A.R. Yavari, On the mechanical properties of TiNb based alloys, J. Alloys Compounds 571 (2013) 25–30.

DOI: 10.1016/j.jallcom.2013.03.192

[7] C.M. Lee, C.P. Ju, J.H. Chern Lin, Structure-property relationship of cast Ti-Nb alloys, J. Oral Rehabilitation 29 (2002) 314-322.

DOI: 10.1046/j.1365-2842.2002.00825.x