Model of formation of droplets during electric arc surfacing of functional coatings

Abstract

Predictions of metal droplet formation in gas metal arc welding. II. Journal of Applied Physics 84, 3530 (1998) Abstract. The mathematical model was developed for the initial stage of formation of an electrode metal droplet in the process of arc welding. Its essence lies in the fact that the presence of a temperature gradient in the boundary layer of the molten metal causes thermo-capillary instability, which leads to the formation of electrode metal droplets. А system of equations including Navier-Stokes equations, heat conduction and Maxwell's equations was solved as well as the boundary conditions for the system electrodes-plasma. Dispersion equation for thermo-capillary waves in the linear approximation for the plane layer was received and analyzed. The values of critical wavelengths, at which thermocapillary instability appears in the nanometer wavelength range, were found. The parameters at which the mode of a finedroplet transfer of the material takes place were theoretically defined.

Nanolayers Formation at Hydrodynamic Instability Development Under the External Energy Effects

“…Вторая роль нанокапель, на взгляд авторов, состоит в генерации теплового удара, за счет которого формируются мощные термоупругие волны, рассмотрение которых при наносекундных воздействиях проведено в работе [48]. Роль упругих волн заключается в повышении ударной вязкости, так как возникшие на первой стадии охлаждения трещины в последующих секциях при взаимодействии упругой волны со свободными берегами трещин захлопываются [49,50].…”