| 摘要 |
Disclosed is a Cu—Ni—Si copper alloy sheet that excels in strength and formability and is used in electrical and electronic components. The copper alloy sheet contains, by mass, 1.5% to 4.5% Ni and 0.3% to 1.0% of Si and optionally contains at least one member selected from 0.01% to 1.3% of Sn, 0.005% to 0.2% of Mg, 0.01% to 5% of Zn, 0.01% to 0.5% of Mn, and 0.001% to 0.3% of Cr, with the remainder being copper and inevitable impurities. The average size of crystal grains is 10 μm or less, the standard deviation of crystal grain size satisfies the condition: 2&sgr;<10 μm, and the number of dispersed precipitates lying on grain boundaries and having a grain size of from 30 to 300 nm is 500 or more per millimeter.
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