Patent ID: 8871041

Claim:
A sheet material of a copper alloy having a chemical composition consisting of 1.2 to 5.0 wt % of titanium, and the balance being copper and unavoidable impurities, said sheet material of the copper alloy having a 0.2% yield strength of 850 MPa or more, wherein the sheet material of the copper alloy has a mean crystal grain size of 5 to 25 μm, and (maximum crystal grain size−minimum crystal grain size)/(mean crystal grain size) is not greater than 0.20, assuming that the maximum value of mean values, each of which is the mean value of crystal grain sizes in a corresponding one of a plurality of regions which are selected from a surface of the sheet material of the copper alloy at random and which have the same shape and size, is the maximum crystal grain size, that the minimum value of the mean values is the minimum crystal grain size and that the mean value of the mean values is the mean crystal grain size, and wherein the sheet material of the copper alloy has a crystal orientation which satisfies I{420}/I 0 {420}>1.0, assuming that the intensity of X-ray diffraction on the {420} crystal plane on the surface of the sheet material of the copper alloy is I{420} and that the intensity of X-ray diffraction on the {420} crystal plane of the standard powder of pure copper is I 0 {420}.