Effect of Flux Composition on Wetting and Spreading of Magnesium over Copper

Composite materials with a porous magnesium matrix and copper reinforcement are promising materials for transport engineering, aviation, energy, and construction. It is possible to form a composite material and a porous structure in a magnesium layer simultaneously in a casting mold by infiltrating liquid magnesium through a layer of granules of water-soluble salts with installed copper reinforcement. To activate the surface and form an adhesive bond when casting composite materials with a magnesium matrix and copper reinforcement, compositions of chloride and chloride-fluoride fluxes, which are widely used in soldering magnesium alloys, have been proposed. On the basis of the studies, compositions of activating fluxes that ensure the spreading of liquid magnesium MG90 and casting alloy ML5 over copper have been established. The effect of the nature of the fluxes and the process temperature on the area of magnesium spreading over the reinforcement has been shown. The adhesion strength of the composite layers when pouring liquid magnesium into a mold with copper reinforcement has been established to be no more than 8 MPa, which is due to the low strength of the Mg2Cu + MgCu2 eutectic formed in the transition layer of the composite.