Mechanical properties and stability of TiPt-M (M = Ru, Co, Cu, Zr and Hf) for high temperature applications

Conference of the South African Advanced Materials Initiative 2018

Mashamaite, M.P.^1 ; 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

关键词: First-principle approach;    Heats of formation;    High temperature shape memory alloy;    High temperatures environment;    Martensitic transformation temperatures;    Partial substitution;    Supercell approach;    Transformation temperatures;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/430/1/012019/pdf
DOI  :  10.1088/1757-899X/430/1/012019

来源: IOP

【 摘 要 】

Shape memory alloys are smart materials that can remember their shape after being deformed. This is due to their unique properties, shape memory effect and super-elasticity, which occurs because of phase transformation. High temperature shape memory alloys are being developed in order to increase the application area of shape memory alloys. There is an increasing demand of shape memory alloys, which can be used in high temperatures environments such as in aerospace, actuators, sensors in the automotive industry. The first-principle approach was employed to investigate the effect of ternary alloying with Ru, Co, Cu, Zr and Hf on the equi-atomic B19 TiPt alloy. The supercell approach based on the B19 TiPt structure was used to construct various compositions containing a third element with reduced Pt content, and evaluate their thermodynamic and mechanical stability. The Ru, Co and Cu calculations were performed to compare their effects on the TiPt relative to Zr and Hf addition. It was found that partial substitution with Ru was the most stable structure as compared to the Hf, since it displayed the lowest heats of formation. Their martensitic transformation temperature increased due to their lowest C′ shear modulus. However, the addition of Cu reduced the transformation temperature of the TiPt. All structures were found to be completely anisotropic.