The invention discloses an ultrahigh-strength high-
conductivity copper alloy. The
copper alloy comprises the following components of, by weight, 4.6-6.0% of Ni, 1.0-2.0% of Co, 1.0-2.0% of Si, 0.05-0.4% of Mg, 0.01-0.1% of Sr, 0.01-0.1% of Nb and the balance Cu, wherein the sum of the
mass percentages of all the components is 100%. The preparation method of the
copper alloy comprises the steps ofsmelting,
casting, homogenization, hot rolling,
solid solution treatment and combined deformation heat treatment. According to the ultrahigh-strength high-
conductivity copper alloy, an element Be which is easy to burn is replaced by elements which are environment-friendly, easy to add and not easy to burn, second-phase particles are separated out through
alloy element component design to prevent
dislocation movement, and meanwhile, the
solid solution elements in a matrix are reduced; a special two-stage hot rolling and
solid solution treatment process is adopted, so that tissues are more uniform, coarse
precipitation phase redissolution is promoted, and
tissue preparation is provided for subsequent deformation heat treatment; and the
precipitation of the nano-reinforced phase is promoted through combined deformation heat treatment, so that the
system alloy has excellent
mechanical property and
conductivity, and the obtained
copper alloy is excellent in
mechanical property and high in conductivity.