Document Type : Research Paper


1 Electromechanical Eng, Dept., University of Technology. Baghdad, Iraq.

2 Computer Engineering Branch, Department of Control and Systems Engineering, University of Technology-Iraq


Because of the unique properties, Ni-Ti based shape memory alloys (SMAs) are increasingly attractive for a wide variety of engineering applications such as actuators, biomedical, or robot coupling. In this work, a third alloying element, namely nanoparticles of Ag (which is insoluble in Ni-Ti matrix), is added by powder technology to the Ni-Ti alloy to produce a Ni-Ti-Ag alloy. The Nanoparticles of the Ag element are added at 3, 5, 7, and 10 wt. % to produce four alloy specimens with different mixtures .The mixing process was done by a horizontal mixer for 120 min with a speed of 350 rpm, and then the mixture was compacted by using a compacting pressure of 600 MPa. Afterward, the compacted specimens were sintered at 600 /min for 6 hrs. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to evaluate the microstructure and phases of the products. DSC examination was used to characterize the phase transformation temperatures in heating and cooling. Wear behavior was defined by using the pin-on-disc technique, and the hardness of the samples was calculated using Vickers's hardness apparatus. The results of this work showed that the nano-Ag added at 7 and 10 wt. % were distributed homogeneously in the Ni-Ti matrix, and that Ag slightly decreased hardness and increased the wear rate. The value of shape memory effect (SME) for the produced alloy was about 89.9% and the phase transformation in heating was at a temperature of about 186.48 and in cooling of about 140.3 for the specimen that contains 10 wt.% Ag nanoparticles.


[1] K. Otsuka, X-Reu, “Physical metallurgy of Ti-Ni based shape memory alloy,” Prog. Material Sci-50 Pf., pp. 511-678, 2005.
[2] N. M. Dawood, M. Juber, “Studied the effect of cooling rate on the phase transformation behavior and hardness of Ni-Ti shape memory alloy,” Vol. 23, No.2, 2015.
[3] R. B. SacZ –Perez, V. R., Maria L, O. A. Ruano and J. S. Juan, “Advanced shape memory alloys processed by powder metallurgy,” Advance Engineering Materials, 2, No. 1-2, pp. 49-53, 2000.
[4] R. M. German, “Powder metallurgy science, metal powder Ind- federation, Princeton,” NJ ,1984.
[5] L. Monographs in P/M series No.1, “Metal powder Ind federation, Princeton,” NJ, 1992.
[6].L. A. Dobrzański, “Powder metallurgy fundamentals and case studies,” Intechopen comp., 2017.
[7] The European Powder Metallugy Associationv, “What is powder metallurgy” article, 2017.
[8] T. H. Nam, D. W. Chung, J. P. Noh, and H. W. Lcc “Phase transformation behavior and wire drawing properties of Ti-Ni- Mo shape memory alloys,” Journal of Material Science, 36, pp. 4181-4188, 2001.
[9] J. Frenzel, E.P. George, A. Dlouhy, C. Somsen, M.X.F. Wagner, and G-Eggeler, “Influence of Ni on martensitic transformation in NiTi shape memory alloys,” Acta Material, 58, pp.3444-3458, 2010.
[10] V. Petzoldt, “Form gedachtnistechrik Tiefbohren and Mikrofrasen Von NiTi: Schriftenreihe ISF, 2006.
[11] A. Bansiddhi and D.C. Dunand, “Shape memory NiTi-Nb foams,” Journal Material Research, 24, pp. 2107-2117, 2009.
[12] W. Bolton, “Engineering materials technology,” Buter worth Heinemann Oxford, 1988.
[13] Marek Novoltny, “Shape memory alloys (SMAs),” 2008.
[14] J. Wan and X. Huang, “Effect of nitrogen addition on shape memory characteristics of Fe-Mn-Si-Cr alloy,” Material Transaction, Vol.43, pp. 920-925, 2002.
[15] M. Bitzer, M. Bram, H. P. Buchxemer and D. Stover, “Phase transformation behavior of hot isostatically pressed NiTi,” Journal of Materials Engineering and performance, Vol. 21, 12, pp. 2535, 2012.
[16] E. S. AL-Hasani, “Preparation and corrosion behavior of NiTi shape memory alloys,” PhD thesis, University of Technology, Baghdad, Iraq, 2007.
[17] S. L. Zhu, X. J. Yang. D. H. Fu, L.Y. Zang, C.Y, Li and Z. D. Cui, “Stress – strain behavior of porous Niti alloys prepared by powders sintering,” Materials Science and Engineering A, 408, 1-2, pp. 264-268, 2005.
[18] V. Kumar, R. Singhal, R. Vishnoi, M. K. Banerjee, M.C. Sharma, K. Asokan and M. Kumar, “Ag implantation – induced modification of Ni-Ti shape memory alloy thin films,” University of Birmingham at 21, 32, 25, 2017.