Microstructures and properties of laser cladding NiTi alloy with W for biomedical applications

The feasibility of improving the radiopacity of NiTi by means of Nd:YAG laser cladding is investigated in the present study. Fine elementary tungsten powder was pasted on NiTi sheets and then melted using laser. The resulting microstructure was analyzed by a scanning electron microscope (SEM) equipped with energydispersive X-ray (EDX) spectrometry. The results show that the solubility of tungsten in the NiTi-matrix is low and the excessive tungsten forms fine precipitates and W-rich compounds, which result in the average W content in the fusion zone up to 8 at.%. The laser-clad sample failed near the end of the plateau with a tensile strength of about 410 MPa. (C) 2011 Elsevier B.V. All rights reserved.