Formation of Intermetallic Coating on 20880 Steel in the Liquid-Phase Inter-Reaction with Aluminum

Abstract

The inter-reaction mechanism of ingot iron with a molten aluminum is proposed and experimentally confirmed. It is shown that the three-layer coating is formed on the surface of ingot iron under the conditions of liquid-phase inter-reaction and consists of bund interlayers of Fe2Al5 and FeAl3 intermetallics and a heterogeneous structure based on solid solution and FeAl3. The micro-hardness of the structural components of the heterogeneous structure ranges from 1 (for Al (Fe)) to 6–9 GPA (for FeAl3+Al (Fe)). An increase in the exposure time during the heat treatment is accompanied by an increase of the quantity of structurally free FeAl3+Al (Fe) fragments in its composition.

Formation of the Diffusion Zone in Explosion Welded Composite Cr20Ni80 - AD1 at Liquid-Phase Interaction

“…The low rate of the intermetallic layer formation and necessity for a subsequent operation to separate the unreacted Al significantly complicate the process of obtaining the diffusion layer based on Ni aluminides and limit its maximum thickness. It is known that a significant increase in the intensity of diffusion processes can be achieved by liquid phase HT of an explosion-welded composite [12]. The aim of this work was to study the structure of diffusion coatings formed on the NiCr-alloy surface after HT of the explosion welded Cr20Ni80 + AD1 bimetal at a temperature exceeding the aluminum melting point.…”