Effect of Alloying with Co on the Formation and Adhesion Strength of Foam Aluminum–Titanium Composite Material

Abstract

The mechanical properties of a layered foam aluminum–titanium composite material produced by the filling of Al melt into molds with pore-forming fluorine fluxes and titanium fixtures are investigated. The shear strength of the composite is determined by the adhesive bond between Al and Ti as well as by the strength of the intermetallic transition layer formed at the interface of the metals. To improve the adhesive bond, titanium is coated with aluminum, and the strength of the intermetallic transition layer is enhanced by alloying it with Co through an Al melt used for aluminizing of titanium. The effect of cobalt alloying on the wetting and spreading of Al melt in titanium during the formation of a composite material is studied. It is shown that alloying with 3% Co reduces the area of spreading of aluminum over titanium. When the titanium surface is activated with the K2TiF6 and K2ZrF6 flux, the wetting of titanium with the melt increases with an increase in the cobalt content, and when activated with KF-AlF3 eutectic, it decreases. Alloying with 2% Co increases the shear strength of the composite owing to the hardening of the intermetallic transition layer. When Ti surfaces are activated with K2ZrF6 flux, the shear strength of composites has the maximum value, which is due to alloying of the transition layer simultaneously with Co and Zr.