| 摘要 |
A copper alloy, which has a chemical composition, in mass %, that Cu: 69 to 88 %, Si: 2 to 5 %, Zr: 0.0005 to 0.04 %, P: 0.01 to 0.25 %, and the balance: Zn, wherein with respect to [a] mass % representing the content of the element a, the relationships: f0 = [Cu]- 3.5[Si] - 3[P] = 61 to 71, f1 = [P]/[Zr] = 0.7 to 200, f2 = [Si]/[Zr] = 75 to 5000 and f3 = [Si]/[P] = 12 to 240 are satisfied, which has a metal structure wherein a phase and ? phase and/or ? phase are present and, with respect to [b] % representing the content of the phase b, the relationships: f4 = [a] + [?] + [?] = 85 and f5 = [?] + [?] + 0.3[µ] - [ß] = 5 to 95 are satisfied, and which has an average crystal grain diameter of 200 µm or less in a macroscopic structure immediately after the solidification of a melt of the alloy. |
