Computational modelling of Ti50Pt 50-XVx potential shape memory alloys

Conference of the South African Advanced Materials Initiative 2018

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

Materials Science and Manufacturing, CSIR, PO Box 395, Pretoria

0001, South Africa^1

Materials Modelling Centre, University of Limpopo, Private Bag X1106, Sovenga, South Africa^2

关键词: Computational modelling;    Elastic properties;    High temperature;    Martensitic transformation temperatures;    Phonon dispersions;    Supercell approach;    Titanium-based;    Vanadium addition;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/430/1/012021/pdf
DOI  :  10.1088/1757-899X/430/1/012021

来源: IOP

【 摘 要 】

The demand for shape memory alloys for high temperatures have increased in recent years and TiPt alloys are promising candidates. The martensitic transformation temperature of TiPt is higher with the value of approximately 1300 K as compared to the commercialised TiNi which transforms at 300 K. Titanium-based SMAs have been widely used in the fields of engineering and medicine due to their shape memory effect (SME) and super-plasticity which are displayed in martensitic transformations. Some of the applications include actuators and medical stents. Previous studies showed that the alloy is mechanically unstable with the negative C′ modulus at 0 K. In this work, supercell approach is used to substitute Pt with vanadium on the B2 TiPt structure and evaluate the mechanical stability of the structures. The equilibrium lattice parameters, elastic properties and the phonon dispersions were calculated to investigate the stability of the Ti50Pt50-XVX. Interestingly the vanadium addition was found to be stabilising the TiPt with all the Cij's being positive.