Impact Temperature in Splat and Splat-Substrate Interface in HVOF Thermal Spraying
— An explicit axisymmetrical FE methodology is developed here to study the particle temperature arising in WC-Co particle on an AISI 1045 steel substrate. Parameters of constitutive Johnson-cook model were used for simulation. The results show that particle velocity and kinetic energy have important role in temperature arising of particles.
Plastic deformation phenomena during cold spray impact of WC-Co particles onto metal substrates
Abstract This paper studies the plastic deformation phenomena in ductile substrates (Al7075 alloy, carbon steel) during cold spray-deposition of WC-Co. Metallographic inspection of etched cross-sections and through-thickness nano-hardness profiling indicate that plastic deformation of the substrate (into which undeformed WC-Co particles penetrate deep) is confined to a shallow area, below which the material appears unaltered. Adiabatic deformation phenomena in the substrate are revealed by finite element modelling of the impact process. Close to the surface, the temperature raises in less than 10 ns, leading to metal jetting, whilst the underlying material, below a depth of few micrometres, is substantially unaffected.
Multi-scale modeling and analysis of an industrial HVOF thermal spray process
A hybrid (deterministic/stochastic) fundamental model is proposed for the major physico-chemical processes involved in an industrial HVOF thermal spray process (Diamond Jet hybrid gun, Sulzer Metco, Westbury, NY, USA). The model includes continuum type differential equations that describe the evolution of gas and particle temperature and velocity, and a rule-based stochastic simulator that predicts the evolution of the coating microstructure. Regarding gas/particle dynamics, the Reynolds- and Favre-averaged Navier–Stokes equations and the energy balance equations are solved with the renormalization group (RNG) k– turbulence model, and the particle trajectories, temperature histories and melting degrees are determined using the fourth-order Runge–Kutta method. On the microscopic particle deposition process, the formation of coating microstructure is captured by the Madejski deformation model and several rules that govern splat formation, solidification and coating growth. Based on the proposed model, a detailed comprehensive parametric analysis is carried out to study the relationship between the key process parameters and the particle in-flight behavior as well as the resulting coating properties. 2005 Elsevier Ltd. All rights reserved.