Electrical discharge machining of a NiAlFe ternary shape memory alloy

• Published in: Journal of alloys and compounds Vol. 464; no. 1; pp. 446 - 451
• Main Authors: Chen, S.L., Hsieh, S.F., Lin, H.C., Lin, M.H., Huang, J.S.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 22.09.2008; Elsevier
• Subjects: Applied sciences; Cutting; EDM; Exact sciences and technology; Metals. Metallurgy; NiAlFe shape memory alloys; Other machining methods; Production techniques; Roughness; NiAlFe shape memory alloys; Roughness; EDM; Ternary alloy; Remelting; Empirical relation; Aluminium alloy; Iron alloy; Electrical discharge machining; Thickness; Hardening; Shape memory alloy; Transition metal alloy; Thermal conductivity; Melting point; Nickel alloy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2007.10.012

The electro-discharge machining (EDM) characteristics of a NiAlFe ternary shape memory alloy (SMA) have been investigated in this study. Experimental results reveal that the material removal rates (MRRs) of Ni 60Al 24.5Fe 15.5 and Ti 35.5Ni 49.5Zr 15 alloys in the EDM process exhibit a reverse relationship to the product of the alloy's melting temperature and thermal conductivity. In addition, a precise EDM machining of NiAlFe SMA can be obtained by setting the machine parameters at low pulse energy. The surface roughness (Ra) of the EDMed NiAlFe SMA is found to follow the empirical equation of Ra = λ( I P × τ P) β . Having a less T Θ × K T value, Ni 60Al 24.5Fe 15.5 alloy has a larger Ra value than that of Ti 35.5Ni 49.5Zr 15 alloy after electro-discharge machining. The recast layer consists of the oxides Fe 2O 3, Al 2O 3, NiO and the deposition particles of the consumed Cu electrode and dissolved dielectric medium. The hardening effect near the outer surface for EDMed NiAlFe alloy originates from the recast layer. The thickness of the recast layer varies with the pulse duration and exhibits a minimum value at the maximal MRR.