EVOLUTION OF THE STRUCTURE AND MECHANICAL PROPERTIES OF COPPER–RON POWDER MATERIAL UNDER THERMOMECHANICAL TREATMENT

Abstract

The feasibility of producing composite powder ribbons in the Cu–Fe system by rolling was examined. Conventional techniques for producing Cu–Fe materials involve the melting of a copper–iron charge. Tehrefore, Cu–Fe composites commonly exhibit relatively low electrical conductivity under the combined effect of the high solubility of iron in copper at elevated temperatures and the slow diffusion kinetics of iron at lower temperatures. Powder metallurgy methods are an alternative to conventional techniques for producing copper–iron composites. They enable the synthesis of materials with the required chemical composition without reaching sintering temperatures that lead to a liquid phase, which prevents the formation of solid solutions in the Cu–Fe system. The influence of rolling parameters and subsequent densifying deformation on the properties of the powder materials was analyzed. Thermomechanical processing parameters were proposed to provide an optimal combination of mechanical properties in the rolled composite products. The mechanical properties of Cu–Fe powder sheet material produced by powder metallurgy were determined not only by the ratio of components but also by the content of oxide impurities in the starting powders. The reduction in the ductility of the rolled ribbons with increasing rolling strain was found to be associated with the accumulation of deformation–induced defects within iron particles and at the copper–iron interface. To mitigate the negative impact on the conductivity of solid solutions near interparticle contacts, the sintering and annealing temperatures for Cu–Fe composite ribbons should be maintained within the range of 600–850 °C.