Microstructure evolution of Cu-22 % in alloy subjected to the high pressure torsion

Abstract

Microstructure studies of Cu-22 wt. % In alloy after annealing and severe plastic deformation were carried out by means of scanning and transmission electron microscopy. Two samples of the alloy were annealed at 350 °C and 520 °C for 553 hours and then subjected to high pressure torsion at room temperature under a pressure of 5 GPa in a Bridgman anvil-type unit. The sample annealed at 350 °C exhibited duplex microstructure: copper matrix with embedded plates of 8 phase (Cu7In3) and 8 phase with lamellar precipitates of copper. The microstructure of the sample annealed at 520 °C consisted of copper matrix with spherical precipitates of 8 phase. The subsequent severe plastic deformation resulted in a substantial grain refinement in copper matrix to nanoscale size. However, the morphology and size of 8 phase precipitates did not change. The measurements of microhardness and calorimetric studies were also performed in order to study the specific properties of 8 phase. © Published under licence by IOP Publishing Ltd.