Analysis and mechanical behavior of coating layer in metallic glass matrix composite

For surface modification, bulk metallic glass coatings were fabricated using metallic glass powder and a mixture of a self-fluxing alloy or/and hard metal alloys with a heat-resisting property using a high velocity oxy-fuel coating thermal spraying process. Microstructural analyses and mechanical tests were carried out using X-ray diffraction, a scanning electron microscope, an atomic force microscope, a three-dimensional optical profiler, and nanoindenation. As a result, the monolithic metallic glass coating was found to consist of solid particle and lamellae regions that included many pores. Second phase-reinforced composite coatings with a self-fluxing alloy or/and hard metal alloy additives were employed with in-situ Cr2Ni3 precipitate or/and ex-situ WC particles in an amorphous matrix. The mechanical behaviors of the solid particles and lamella regions showed large hardness and elastic modulus differences. The mechanical properties of the particle regions in the metallic glass composite coatings were superior to those of the lamellae regions in the monolithic metallic glass coatings, but indicated similar trends in matrix region of all the coating layers.