Laser melt injection of niobium carbide on aluminium bronze substrates for enhanced cavitation erosion resistance

Cavitation erosion (CE) is detrimental to a number of engineering components, including ship propellers and pump impellers. Due to deformation and mass loss, CE significantly impairs the serviceability of these components and results in tremendous economic loss. Therefore, the demand for a reduction in material damage due to CE is imperative. Material damage can be minimised by using protective layers tailored to resist CE. In this work, laser melt injection (LMI) was performed to improve the cavitation erosion resistance. A metal matrix composite (MMC) is formed on the aluminium-bronze substrates by injecting niobium carbide (NbC). The impact of different particle sizes on the CE behavior of the reinforced surface layer was investigated. CE tests of produced layers and untreated aluminium bronze are carried out as per ASTM G32-16 standard and the results are compared. The dependency of coating microhardness, and fracture toughness of particles on the cavitation erosion is discussed. The results show that the small NbC particle-reinforced sample exhibited an improvement of approximately 69% in CE resistance compared to the untreated NAB sample.