Enhancing the wear resistance of sintered WC-Co composite by adding pseudo-elastic TiNi constituent

It has long been demonstrated that pseudoelastic TiNi alloy possesses high resistance to wear due to its rubber-like behavior that helps to accommodate deformation and elevate the capability of absorbing impact energy to mitigate the damage from wear attacks. In this study on WC-Co composite, which has found many applications in forms of coating, hardfacing overlay and bulk against wear, we added near equiatomic TiNi alloy powder to the WC-Co composite for improved wear resistance. WC-Co samples containing different amounts of TiNi were sintered using a hot isostatic pressing (HIP) process. It was demonstrated that markedly enhanced wear resistance was achieved when TiNi powder was added to the WC-Co composite. The sintered WC-Co-TiNi specimens were analyzed using the X-ray diffraction technique (XRD) and scanning electron microscopy (SEM). It was observed that a certain degree of decomposition of the added TiNi occurred during the sintering process. In order to clarify the mechanism responsible for the improvement to the wear resistance, local mechanical properties of different domains, including hardness, Young's modulus and the ratio (eta) of elastic deformation energy to the total deformation energy, were evaluated using a micro-indenter. Based on the microstructure characteristics and micro-mechanical properties of different domains, efforts are made to understand the role that the added TiNi powder played in enhancing the wear resistance of the WC-Co composite. (C) 2011 Elsevier B.V. All rights reserved.