Abstract: A copper-nickel-silicon-chromium alloy having the combination of high hardness and high electrical conductivity. The alloy is composed by weight of 9.5% to 11.5% nickel, in an amount sufficient to provide a nickel-silicon ratio of 3.4 to 4.5, 0.5% to 2.0% chromium, and the balance copper. The alloy is heat treated by initially heating the alloy to a solution temperature and is thereafter quenched. The quenched alloy is then aged to precipitate the metal silicides. Because of the specific ratio of nickel to silicon, the heat treated alloy develops during heat treatment a hardness in excess of 30 Rockwell C and an electrical conductivity in excess of 24% of pure copper.

Abstract: A copper-nickel-silicon-chromium alloy having a high hardness and improved electrical conductivity. The alloy is composed by weight of 2.0% to 3.0% nickel, 0.4% to 0.8% silicon, 0.1% to 0.5% chromium, and the balance copper. The silicon is used in excess of the stoichiometric relationship with nickel to provide excess silicon, and the chromium is used in excess of the stoichiometric relationship with the excess silicon. The alloy is heat treated by initially heating the alloy to a temperature in the range of 1600.degree. F. to 1800.degree. F. and is thereafter quenched. The quenched alloy is then subjected to a two-step aging treatment in which the alloy is initially aged at a temperature of 900.degree. F. to 1100.degree. F. to precipitate the metal silicides and develop a hardness in excess of 90 Rockwell B (185 Brinell) and subsequently is subjected to a second aging at a temperature in the range of 750.degree. F. to 900.degree. F.

Abstract: A copper-nickel-silicon-chromium alloy having a high hardness and improved electrical conductivity. The alloy is composed by weight of 2.0% to 3.0% nickel, 0.4% to 0.8% silicon, 0.1% to 0.5% chromium, and the balance copper. The silicon is used in excess of the stoichiometric relationship with nickel to provide excess silicon, and the chromium is used in excess of the stoichiometric relationship with the excess silicon. The alloy is heat treated by initially heating the alloy to a temperature in the range of 1600.degree. F. to 1800.degree. F. and is thereafter quenched. The quenched alloy is then subjected to a two-step aging treatment in which the alloy is initially aged at a temperature of 900.degree. F. to 1100.degree. F. to precipitate the metal silicides and develop a hardness in excess of 90 Rockwell B (185 Brinell) and subsequently is subjected to a second aging at a temperature in the range of 750.degree. F. to 900.degree. F.