Influence of copper addition on the properties of equiatomic NiTi shape memory alloy prepared by vacuum induction melting method

• Published in: Journal of physics. Conference series Vol. 1963; no. 1; pp. 12017 - 12023
• Main Authors: Mohammed, Safa H., Mohammed, Mudhafar A., Aljubouri, Ali A., Shahatha, Sara H.
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.07.2021
• Subjects: Alloying elements; Body temperature; Composition; Copper; DSC; Heat treatment; Intermetallic compounds; Martensitic transformations; Microhardness; Nickel base alloys; Nickel compounds; Nickel titanides; NiTi shape memory alloys; Optical microscopes; phase transformation; Shape memory alloys; shape memory materials; Titanium compounds; Transformation temperature; Vacuum induction melting; XRD
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/1963/1/012017

Abstract In this study the effect of Cu addition on the phase transformation behavior, microstructure, and micro hardness of equiatomic Ni-Ti shape memory alloy was investigated. NiTiCu SMA prepared with the composition (52.119 % at. Ni, 41.731% at. Ti and Cu 6.15 % at.) and compared with the properties of the equiatomic NiTi SMA with composition (50% at. Ni, 50% at. Ti). Vacuum induction melting method used in the preparation of Both SMAs. The Differential Scanning Calorimetry, Scanning Electron Microscope, X-ray Diffraction Analysis, optical microscope and vicker’s microhardness test was used to investigate the characteristics of the equiatomic NiTi and NiTiCu SMAs. The results revealed that when Cu element was added the phase transformation temperatures decreased below body temperature. NiTi matrix phase and Ti2Ni secondary phase exist in both SMA samples, also Cu-rich phase appeared in NiTiCu SMA and this is one of the reasons that lead to increasing the microhardness of alloy when Cu element was added. The value of equiatomic NiTi increases from 238.74 to 329 when Cu element was added (for NiTiCu alloy) after heat treatment.