Indian Journal of Engineering & Materials Sciences Vol. 26, October-December 2019, pp. 363-368 Friction and wear behaviors of Fe-14Mn-9Cr-5Ni-6Si and Fe-13Cr-12Co-8Mn- 6Ni-6Si shape memory alloys Amine Charfi*, Mohamed Trabelsi & Mohamed Kharrat University of Sfax, Laboratory of Electromechanical Systems (LASEM-ENIS), Sfax (Tunisia) Received: 23 May 2018; Accepted: 26 July 2019 Iron-based shape memory alloys are the materials that can be especially used in civil engineering structures and pipe coupling because of their good mechanical properties and their low price compared with Ni-Ti and cooper-based alloys. However, their applications have been remained limited so it is very important to determine the wear behaviours of this family of materials. This paper presents friction and wears behaviours of Fe-14Mn-9Cr-5Ni-6Si and Fe-13Cr-12Co-8Mn- 6Ni-6Si under both dry and lubricated conditions by means of reciprocating ball-on-flat tribometer. The aim of this study is to determine the influence of chemical composition of iron-based shape memory alloys on tribological behaviours of material and compare their behaviours with that of Fe-32Mn-6Si which is considered as a basis reference. Morphologies and microstructures of specimens have been characterized by optical microscope. The wear tests and the optical micrograph observations of studied alloys have shown that the tribological behaviors of shape memory alloys depend on the chemical composition of material which is mainly influenced by the presence of nickel, chromium and cobalt in material. The results have shown that friction coefficients of Fe-14Mn-9Cr-5Ni-6Si and Fe-13Cr-12Co-8Mn-6Ni-6Si are almost equal and less than of Fe-32Mn-6Si. Moreover, the addition of cobalt in the chemical composition of shape memory alloys reduces considerably the stick-slip phenomenon. It has been also shown that wear resistance of alloys in oily friction is higher than that in dry friction. Keywords: Iron-based shape memory alloys, Friction behavior, Wear behavior 1 Introduction Iron based shape memory alloys (SMAs) are very interesting to use because of their low cost, their high mechanical strength, fine workability 1 as well as their good tribological properties 2 . Despite their distinctive properties, iron-based shape memory alloys are currently used only in a few practical applications such as tighteners or pipe couplings 3 and civil engineering 4 such as in buildings of bridges 5 . These materials can be used also as external end-fixed reinforcements to strengthen reinforced concrete structures 6 . For these applications, the wear performance of material plays an important role in ensuring its durability. The shape memory effect of iron based shape memory alloys is explained by the reverse transformation of the hexagonal (ε) marten site to the face centered cubic (fcc) (γ) austenite phase’. Iron based shape memory alloys are limited by their poor corrosion resistance 7-9 , the addition of chromium, nickel and cobalt improve this chemical property. However, the cost of these new nuances becomes less attractive for many applications 10,11 . In Fe-Mn-Cr shape memory alloys, a high quantity of Cr increases the stacking fault energy and suppresses the formation of marten site which allows the stability of austenite 12 . Many research works have been carried out on Ni-Ti in regards to welding and joining 13 , physical metallurgy 14 , finite element modeling of Ni-Ti orthodontic wires 15 and fatigue study of thin films 16 . Others research works has been done on copper-based alloys that can replace NiTi in many applications for their reduced cost and excellent super elasticity. These materials have shown their efficiencies essentially for damping systems in seismic devices 17 . For iron-based shape memory alloys, studies were interested in the factors that promotes the martensitic transformation such as thermo-mechanical training 18,19 , effect of the pre-deformation 20 and characterization of wear resistance 21,22 . Authors concluded that wear rate decreases with hardness of materials 22,16 . For Fe–17Mn–5Si–10Cr–4Ni alloys, Chengxin et al. Observed the presence of large amounts of marten site in the worn surface of alloys in oily friction, which is on the contrary in dry friction 21 . The high wear resistance of iron-based shape memory alloys in oily friction is the result of the stress-induced martensitic ——— *Corresponding Author (E-mail:charfiamin33@gmail.com)