Microstructure and properties of ultra-fine grain Cu-Cr alloy prepared by equal-channel angular pressing

Ultra-fine grain (UFG) Cu-Cr alloy is prepared by equal-channel angular pressing (ECAP). The microstructure, tensile and fatigue properties of the UFG Cu-Cr alloy were investigated. The bulk materials with average grain size of similar to 230 nm were obtained through ECAP for 12 times. The cellular subgrains with low-angle grain boundaries were first formed at relatively low strains, and high-angle grain boundaries dominate the microstructure with the increasing of strains. Materials exhibit homogeneous equiaxed subgrains after ECAP processing. The Cu-Cr alloy processed by ECAP has high strength besides high conductivity and sufficient ductility. Fatigue experiments were carried out in terms of stress-controlled for the 4 and 6 passes ECAPed samples. The increase of fatigue limit and prolong of fatigue life are remarkable as compared with those of coarse grain Cu-0.75Cr alloy and ECAPed pure Cu reported in available literatures. (C) 2007 Elsevier B.V. All rights reserved.