Study of the reinforcement phase dilution into the metal matrix in functionally graded Stellite 6 and WC metal matrix composite by Laser Metal Deposition

Abstract

Metal Matrix Composite (MMC) coatings have become increasingly important in recent years because of their high wear resistance in aggressive environments. These coatings can be efficiently manufactured by Laser Metal Deposition, as it is known to perform well in repair and coating applications due to its low substrate affection. However, there are many challenges to be faced when metallic and ceramic materials are combined. In fact, inhomogeneous material distribution and lack of metallurgical integrity are issues to be addressed. For this purpose, the use of Functionally Graded Materials is proposed. Nevertheless, there is a lack of knowledge regarding the procedure and deposition strategies to follow in order to obtain crack-free coatings.In the present work, the main challenges for the deposition of such coatings have been experimentally identified, particularly for Stellite 6 reinforced with tungsten carbide. To that end, the quality of the deposited coatings and their composition has been assessed. Furthermore, as the dilution of the reinforcement phase has not been studied in depth in the literature when ceramic particles are used, in the present study, an analysis of the dilution of the ceramic phase in the metal matrix is performed when different WC concentrations are fed.