Production of the 70% Cu-30% Fe Alloy by SHS Metallurgy and Electrometallurgy: Comparative Analysis of Microstructures

The influence of different methods of producing alloys of the Fe-Cu system from immiscible components is studied. Alloys with limited solubility (LS) in liquid and solid states are impossible to fabricate by conventional metallurgy. This is why developing low-cost and simple technologies for fabricating such alloys and materials based in them, making it possible to specify the necessary level of physicomechanical properties, is currently a relevant problem. Energy-effective SHS metallurgy is used for the first timchemical scheme of the synthesis ofe in this work to prepare a pseudoalloy with a composition, wt %, of 70Cu-30Fe from oxide materials. This technology offers the use of chemical energy liberated during the interaction of highly exothermic thermite compositions (in a combustion mode), which makes this method one of most energy-efficient for cast material production. The short synthesis time (tens of seconds) and protection of the top ingot surface by the oxide melt (Al2O3) against oxidation make it possible to perform the process in atmospheric conditions. Rods with the same composition have been fabricated by vacuum induction smelting from pure (impurity-free) components Fe and Cu for a comparative analysis of structural components of alloy samples. It is revealed that the high temperatures of the melt of the SHS alloy provide an increased solubility of Cu in Fe. Then structural components are isolated during the crystallization in the form of finely dispersed particles over the entire volume, forming the hierarchical structure characteristic for the SHS alloy only. The 70Cu-30Fe alloys formed in the combustion mode (SHS) have a uniform homogeneous structure with a uniform distribution of all structural components over the sample volume, which can be of great practical interest, in particular, when developing isotropic and anisotropic hard-magnetic materials with high magnetic energy.