The Microstructure, Wear Resistance and Corrosion Behaviour of Ti64l4V+W Composite in 3.5 wt% NaCl Solution of Laser Metal Deposition

Abstract

The polarisation current density, the open circuit potential (OPC) and the corrosion rate of the Ti6Al4V+W coating prepared using a 3.5 wt% NaCl solution were analysed. The corrosion tests performed on a coated sample of Ti6Al4V+W revealed excellent corrosion resistance that was kinetic active and steady in a NaCl solution. Surface integrity of Ti6Al4V was improved after the inclusion of W particles. Laser deposition process was used with different laser power of 800, 900, 1000, 1200 and 1400 W with a constant scanning of 0.5 m/min. The best corrosion resistance was observed at a laser power of 1000 W with a scanning speed of 0.5 m/min. The highest hardness was also observed at a laser power of 1000 W. The scanning electron microscopy (SEM) was used to provide a high amplification image and high magnification image of the specimen. The laser metal deposition (LMD) procedure has turned out to be one that is supportable. The results show that low scanning speed has a higher groove depth. The relationship between scanning speed and groove depth correlates with wear performance. SEM was also used to analyse the microstructures of the coated sample. The microstructures of Ti6Al4V+W displayed the white core-rim structure and the black core-rim structure. With the addition of W, the inner rim increased.

This work is supported by National Laser Centre, Pretoria, South Africa.