Effect of temperature conditions during exothermic remelting of thermite charges on the strength of iron-aluminum alloys

Abstract

Owing to their wear resistance and high corrosion resistance, iron-aluminum intermetallic alloys are used in aircraft engineering, shipbuilding, and mechanical engineering, mainly as protective coatings for structural components operating at elevated temperatures or in corrosive media. Interest in these alloys is largely driven by the wide availability and relatively low cost of their constituent elements. However, multistage, complex routes required to develop the target microstructure and properties, along with the costly equipment involved, hinder the wider adoption of binary iron-aluminum alloys and limit the range of products made from them. A potential alternative to conventional production routes for Fe-Al alloys is the single-stage exothermic remelting of thermite charges composed of fractions of an aluminum-containing alloy mixed with metallurgical mill scale. This approach not only enables the recycling of hard-to-utilize industrial by-products, but also makes it possible to produce fully intermetallic components. A series of preliminary experiments demonstrated that several process parameters of exothermic remelting can be controlled, thereby affecting the final alloy chemistry, microstructure, and microhardness. The novelty of this work lies in evaluating the combined effect of the thermite-charge component ratio and the process temperature conditions on the compressive strength and fracture behavior of specimens produced from experimental iron-aluminum alloys.