Laser MMC Cladding for Wear-Resistant Metallurgical Bonding

The patent changes the thermal process parameters by using controlled heating cycles with specific temperature ranges (below melting point of base material) and cooling rates to achieve metallurgical bonding without excessive porosity. The heating cycle brings the substrate and coating to a temperature range that enables diffusion bonding, while the cooling cycle controls solidification to minimize void formation.

The patent uses composite coating materials containing hard phase particles (such as carbides, oxides, or intermetallics) dispersed in a metal matrix. This composite structure provides both wear resistance from the hard particles and bonding capability from the metal matrix, resolving the contradiction between wear resistance and bond strength.

The patent transforms the deposition process from high-velocity impact (thermal spraying) to controlled thermal processing. By using heating cycles that bring materials to sub-melting temperatures followed by controlled cooling, the process achieves metallurgical bonding with minimal residual stresses and porosity, improving coating quality while maintaining broad substrate applicability.

The patent replaces the mechanical impact mechanism of thermal spraying with a thermal-diffusion mechanism. Instead of relying on kinetic energy to embed particles, the process uses controlled heating to enable atomic diffusion and metallurgical bonding, eliminating the harmful mechanical impacts that cause porosity and residual stresses.

The patent replaces the high-velocity mechanical impact process with a controlled thermal processing approach. By using heating cycles that enable diffusion bonding at lower temperatures and velocities, the process eliminates oxidation caused by high-speed particle flight through air and prevents residual stresses from rapid deceleration and impact.

The patent creates a protected thermal environment during deposition, either through vacuum conditions or inert gas atmosphere, preventing oxidation of the coating material and substrate during the heating and cooling cycles. This allows controlled thermal processing without the harmful oxidative effects present in conventional thermal spraying.

The patent applies partial heating by using controlled heating cycles that raise the temperature only to the range required for diffusion bonding, below the melting point of the base material. This partial thermal action achieves metallurgical bonding while minimizing the heat-affected zone and preventing excessive dilution of the coating material.

The patent uses periodic heating and cooling cycles to achieve controlled thermal processing. The heating phase brings the substrate and coating to bonding temperature, while the cooling phase solidifies the joint with minimal heat input. This periodic action enables metallurgical bonding while limiting the overall heat-affected zone and reducing dilution.