Abstract: [Object] To provide a Cu—Ti-based copper alloy sheet material having a strength, an electrical conductivity, bending workability, and a stress relaxation property all at high levels in a good balance, and also having a reduced density (specific gravity). [Means for Solution] A copper alloy sheet material composed of, in mass %, Ti: 1.0 to 5.0%, Al: 0.5 to 3.0%, Ag: 0 to 0.3%, B: 0 to 0.3%, Be: 0 to 0.15%, Co: 0 to 1.0%, Cr: 0 to 1.0%, Fe: 0 to 1.0%, Mg: 0 to 0.5%, Mn: 0 to 1.5%, Nb: 0 to 0.5%, Ni: 0 to 1.0%, P: 0 to 0.2%, Si: 0 to 0.5%, Sn: 0 to 1.5%, V: 0 to 1.0%, Zn: 0 to 2.0%, Zr: 0 to 1.0%, S: 0 to 0.2%, rare earth elements: 0 to 3.0%, and the balance substantially being Cu, wherein a maximum width of a grain boundary reaction type precipitate existing region is 1000 nm or less, a KAM value when a boundary with a crystal orientation difference of 15° or more measured by EBSD (step size: 0.1 ?m) is rewarded as a crystal grain boundary is 3.

Abstract: [Object] To provide a Cu—Ti-based copper alloy sheet material having a strength, an electrical conductivity, bending workability, and a stress relaxation property all at high levels in a good balance, and also having a reduced density (specific gravity). [Means for Solution] A copper alloy sheet material composed of, in mass %, Ti: 1.0 to 5.0%, Al: 0.5 to 3.0%, Ag: 0 to 0.3%, B: 0 to 0.3%, Be: 0 to 0.15%, Co: 0 to 1.0%, Cr: 0 to 1.0%, Fe: 0 to 1.0%, Mg: 0 to 0.5%, Mn: 0 to 1.5%, Nb: 0 to 0.5%, Ni: 0 to 1.0%, P: 0 to 0.2%, Si: 0 to 0.5%, Sn: 0 to 1.5%, V: 0 to 1.0%, Zn: 0 to 2.0%, Zr: 0 to 1.0%, S: 0 to 0.2%, rare earth elements: 0 to 3.0%, and the balance substantially being Cu, wherein a maximum width of a grain boundary reaction type precipitate existing region is 1000 nm or less, a KAM value when a boundary with a crystal orientation difference of 15° or more measured by EBSD (step size: 0.1 ?m) is rewarded as a crystal grain boundary is 3.