Study of Micro-Abrasive Wear Resistance of Heat Treated NiTi Alloys

Abstract

The Nickel Titanium (NiTi) alloy is a shape memory alloy. It presents two distinct properties: shape memory effect (martensite phase at room temperature) and the pseudoelasticity (austenite phase at room temperature). These materials are frequently used in industries like engineering, dentistry, medicine and aeronautics, and for certain applications it is important to know the wear behavior of these alloys.Thus, this study aims to evaluate the micro-abrasive wear behavior of pseudoelastic NiTi alloys at the as received and aged conditions, and compare with results obtained for NiTi alloy with shape memory effect. The aging heat treatment was performed at temperatures of 350, 450, 500 and 600 °C with an isotherm of 30 minutes and subsequent quenching in water. The wear tests were carried out in a free ball machine. After wear testing was observed that the wear coefficient obtained were lower for all treatment temperatures when compared to pseudoelastic NiTi alloy as received, reducing wear by 30 % in case of treatment at 350 °C. The alloy with shape memory effect showed good wear behavior, with a wear coefficient about 14 % less than the untreated pseudoelastic NiTi alloy.