Abstract:Cu-Cr-Co-Ti alloys were prepared by vacuum induction melting and two-step cryorolling-aging (CRA) process. The room-temperature and elevated-temperature properties of the peak-aged samples were investigated, respectively. The microstructures of Cu-CrCo-Ti samples were analyzed using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The results showed that CRA treatment could introduce the high-density deformation twin bundles, dislocations, and nanoscale precipitates, thus improving the room-temperature strength and electrical conductivity. The nanoscale precipitates with a face-centered cubic (fcc) structure distribute uniformly in matrix and obtain the orientation relationship of cube-on-cube with matrix. Co and Ti elements tended to aggregate at the periphery of nanoscale Cr precipitates to restrain it coarsening and growth during the aging treatment and elevated-temperature deformation. After the elevated-temperature tensile tests at 300 ℃, the nanoscale Cr precipitate could impede the motion of grain boundary, leading to the optimization of elevated-temperature properties. The room-temperature strength (571 MPa) and electrical conductivity (73.9%IACS, IACS: International Annealed Copper Standard) of peak-aged CRA sample were obtained after aging at 500 ℃ for 2 h. The high-density twin bundles with excellent thermal stability could elevate the elevated-temperature tensile strengths at 300 ℃ and 400 ℃ to 481 MPa and 379 MPa, respectively.