Peridynamic study of elevated-temperature particle impact in HVAF deposition of MCrAlY bond coat

High-Velocity Air-Fuel (HVAF) shows strong potential as a promising technique for depositing high-quality MCrAlY bond coats. In the HVAF process, combustion of air with a fuel such as propylene generates high-velocity, relatively low temperature particles, enabling solid-state deposition due to reduced thermal load. Given the challenges in experiments to capture transient impact process and interfacial evolution at characteristic temporal and spatial scales, numerical simulations are often employed as an effective approach to study the particle impact behaviors and subsequent coating build-up process. The accuracy and predictive capability of numerical simulations are highly dependent on the constitutive relation, for which the Johnson-Cook (JC) model is widely used. However, available parameterization of JC model is rather scarce for the particle materials used for MCrAlY bond coats, with none available for NiCoCrAlHfYSi. In the present study, experiments were carried out to measure metrics including particle impact velocity, oxide thickness, temperature, and deformation characteristics during the HVAF process. At the same time, a series of peridynamic simulations with sensitivity analysis on JC parameters were performed to quantify their relative importance to the deformation response. Subsequently, a weighted regression fitting strategy has been developed to identify the JC parameters on base of the measured experimental metrics, ensuring good agreement between simulation and experimental results. This study provides a general route for calibrating constitutive relations for reliable numerical modeling of particle deposition and coating build-up during the HVAF process.