Spark Plasma Sintering and Hot Pressing of Cu+Al Powder Mixtures and Pre-Deposited Cu/Al Layers

Reactive processing of metals is interesting for materials design and achieving new sets of properties. The transformation degree of the metals, the factor governing the properties of the material as a whole, depends on the sintering/heat treatment conditions. In the present investigation, the phase and microstructure formation of materials obtained by sintering of Cu-10 wt.% Al mixtures and layered Cu/Al structures under different modes of pressing/heating is presented. The samples were obtained via spark plasma sintering (SPS), hot pressing (HP) and pressureless sintering. The products of the interaction between the metals were Al2Cu and Cu9Al4 intermetallics and Cu(Al) solid solutions. The influence of the consolidation method on the phase composition of the sintered materials was studied. The hardness of the composites was analyzed in relation to their structural features. A model experiment has been conducted to trace the structural evolution at the Cu/Al interface caused by interdiffusion. The Cu/Al layered structures obtained by detonation spraying of the powders on a steel substrate were treated by SPS or HP. The effect of electric current, which is a feature of SPS processing, was in accelerating the reaction product formation in the layered structures still containing the starting metallic reactants.