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.
Computer simulations and theory of oceanographic fluorescence lidar signals: effect of sea surface structure.
A 3-D computer simulation model has been developed using geometrical optics suitable for analyzing the effect of sea surface structure on oceanographic fluorescence lidar signals. Depth-resolved and depth-integrated signals reveal a considerable dependence on the surface structure. The results obtained by simulation are confirmed by a theoretical approach based on the transformation of solid angles by curved boundaries. Using statistical assumptions about the distribution of curvatures of the ocean surface, a general expression for this influence is found.