Thermal Stability of Mechanical Properties of Copper after Equal-Channel Angular Pressing

Abstract

Annealed oxygen-free and tough-pitch copper samples have been processed by equalchannel angular pressing (ECAP) by route BC. The samples included 8 x 8 mm section pieces and a 40 mm diameter bar. Thermal stability was assessed based on the changes in the standard mechanical properties (conventional yield strength, tensile strength, elongation, proportional elongation and contraction) after annealing at different temperatures for 1 hour. Thermal stability of the same grade of material has been found to be different for different batches and to depend on the structural conditions of deformed material. The zone of thermal stability for copper of the two grades of interest does not depend on the material’s chemical composition.

Study of Thermal Stability of Ultrafine-Grained Copper by means of Electron Back Scattering Diffraction

“…These changes in microstructure result in changes of mechanical properties like microhardness, tensile characteristics and fatigue life. [2][3][4][5] The degree of ''temperature effect'' depends on the magnitude of strain imposed during the SPD process, i.e. on the number of passes through ECAP die and on the temperature of annealing.…”