Effect of different reducing agents on phase formation and transformation behaviour of Ni-Ti shape memory alloy

International Conference on Advances in Manufacturing and Materials Engineering 2017

机械制造;材料科学

Mohd Zaki, H.H.^1 ; Bahrudin, N.A.^1 ; Abdullah, J.^2 ; Sarifuddin, N.^1

Department of Manufacturing and Materials Engineering, International Islamic University Malaysia (IIUM), Jalan Gombak, Kuala Lumpur

53100, Malaysia^1

School of Mechanical Engineering, Universiti Sains Malaysia, Seri Ampangan, Nibong Tebal, Penang

14300, Malaysia^2

关键词: Energy dispersive;    Enthalpy change;    NiTi shape memory alloys;    Phase formations;    Powder X ray diffraction;    Reducing environment;    Solid state sintering;    Transformation behavior;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/290/1/012048/pdf
DOI  :  10.1088/1757-899X/290/1/012048

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

In this study, NiTi synthesized via solid-state sintering from Ni-TiH2powders in reducing environments using (i) CaH2(ii) MgH2and (iii) CaH2and MgH2as in situ reducing agent were investigated. The phase formation was characterized by means of scanning electron microscope (SEM), energy-dispersive spectroscope (EDS) and powder X-ray diffraction (XRD), while transformation behavior was analyzed using differential scanning calorimetry (DSC) measurement. Among these three reducing agents, synthesis in reducing environment using CaH2as in situ reducing agent resulted in the formation of single phase NiTi with enthalpy change of 25-26 J/g, which is similar to melt-cast NiTi alloys. Specimens sintered in reducing environments using MgH2and MgH2+CaH2as in situ reducing agents have lower enthalpy change, ∼16-21 J/g compared to CaH2. This work established the fact that, synthesis in different reducing environment appears to have profound effects on the phase formation and transformation behavior of NiTi.