Optimization, Microstructure, and Properties of Ti-6Al-4 V Coatings Fabricated by Laser Cladding

In this paper, Ti-6Al-4 V alloy coatings were fabricated by the laser cladding process on TC4 alloys using a coaxial powder feed method. By setting orthogonal test, surface quality evaluation basis, and grey relational analysis method, the effect of each parameter on the cladding process was investigated and the optimal parameters for laser cladding were gained. Furthermore, a comprehensive study was performed on the different powder feed rates on morphology, microstructure, micro-hardness and tribological properties of the coatings. The results show that the optimized process can produce better cladding coatings. The microstructure of the Ti-6Al-4 V coatings is mainly composed of columnar β-grains and martensites α′. It was also seen that the micro-hardness of the coatings prepared at a powder feed rate of 16 g min−1 was greater than TC4 substrate and other claddings because the amount of martensites α' increases initially and then decreases. As a result, the friction coefficient and wear loss of the coatings decrease initially and then increase with the increase in the powder feed rate, indicating that the wear resistance of the coatings generated at 16 g min−1 is best.