Computational study of binary titanium-based potential shape memory alloys

Conference of the South African Advanced Materials Initiative 2018

Baloyi, M.E.^1 ; Modiba, R.^2 ; Chauke, H.R.^1 ; Ngoepe, P.E.^1

Materials Modelling Centre, School of Physical and Mineral Sciences, University of Limpopo, Private Bag X1106, Sovenga

0727, South Africa^1

Council for Scientific and Industrial Research, CSIR, Materials Science and Manufacturing, Lynnwood Manor, P.O. Box 395, Pretoria

0001, South Africa^2

关键词: Computational studies;    First-principles density functional theory;    Heats of formation;    High temperature shape memory alloy;    Mechanically stable;    Phonon dispersion curves;    Relative stabilities;    Thermodynamically stable;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/430/1/012020/pdf
DOI  :  10.1088/1757-899X/430/1/012020

来源: IOP

【 摘 要 】

First-principles density functional theory approach was employed to investigate the martensitic temperature of the equiatomic TiPt, TiZr and TiTa shape memory alloys. Firstly, their structural, thermodynamic, elastic and phonon dispersion have been deduced to mimic the relative stabilities. These alloys have potential to operate as high-temperature shape memory alloys since they possess a reversible B2 to B19 martensitic transformation. It was found that the lattice parameters are in good agreement with the experimental results to within 5%. Furthermore, the TiPt structure is thermodynamically stable displaying lowest heats of formation, while TiZr and TiTa are not. Our results show that the B2 phases of these binary alloys are vibrational unstable due to the presence of soft modes along high symmetry direction on the phonon dispersion curves. TiTa alloy is mechanically stable (C′ > 0), which may be used to develop future high-temperature alloys.