Influence of alloying with hafnium on the microstructure, texture, and properties of Cu-Cr alloy after equal channel angular pressing

摘要

Equal channel angular pressing (ECAP) results in grain refinement of the Cu-0.7 % Cr alloy with an average grain size of 320 +/- A 73 nm. Addition of hafnium leads to a further decrease of average grain size down to 225 +/- A 82 nm and to an increase of the fraction of high angle boundaries from 40 to 53 %. The microhardness of the Cu-0.7 % Cr-0.9 % Hf alloy is higher than that of the Cu-0.7 % Cr alloy in the quenched state, after ECAP followed by annealing in the temperature interval of 400-550 A degrees C during which aging occurs. Compared with the quenched state, ECAP increases the tensile strength of the Cu-0.7 % Cr and Cu-0.7 % Cr-0.9 % Hf alloy by a factor of 2.3 and 2.2, respectively. Aging leads to additional strengthening. Compared with the Cu-0.7 % Cr alloy, the strength of the Cu-0.7 % Cr-0.9 % Hf alloy after ECAP and after subsequent aging is 1.3 and 1.5 times higher, respectively.