Copper alloy and process for producing copper alloy

Abstract

To provide a copper alloy of the FCC structure containing Ni: 3.0 to 29.5 mass %, Al: 0.5 to 7.0 mass %, and Si: 0.1 to 1.5 mass %, with the remainder consisting of Cu and incidental impurities, wherein the copper alloy is of the high strength, but is excellent in workability, and has high electrical conductivity, and can control property thereof, by precipitating a γ′ phase of the L1 2 structure including Si at an average particle diameter of 100 nm or less in a parent phase of the copper alloy.

1 . A high strength copper alloy of the FCC structure containing Ni: 3.0 to 29.5 mass %, Al: 0.5 to 7.0 mass %, and Si: 0.1 to 1.5 mass %, with the remainder consisting of Cu and incidental impurities, wherein a γ′ phase of the L12 structure is precipitated with Ni3Al comprising Si at an average particle diameter of 100 nm or less in a parent phase of the copper alloy. 
     
     
         2 . The high strength copper alloy according to  claim 1 , wherein the high strength copper alloy contains Ni: 3.0 to 14.0 mass %, Al: 0.5 to 4.0 mass %, and Si: 0.1 to 1.5 mass %, and has electrical conductivity of 8.5 IACS % or more. 
     
     
         3 . The high strength copper alloy according to  claim 2 , wherein cold workability is in a range of 10 to 95%. 
     
     
         4 . The high strength copper alloy according to  claim 2 , wherein the high strength copper alloy is in a region A surrounded by four points of (Al: 2.0 mass %, Ni: 3.0 mass %), (Al: 4.0 mass %, Ni: 9.5 mass %), (Al: 1.5 mass %, Ni: 14.0 mass %), and (Al: 0.5 mass %, Ni: 5.0 mass %), as a range represented by Al equivalent (mass %)=(Al mass %+1.19Si mass %) and Ni mass %. 
     
     
         5 . The high strength copper alloy according to  claim 1 , wherein the high strength copper alloy contains Ni: 9.5 to 29.5 mass %, Al: 1.5 to 7.0 mass %, and Si: 0.1 to 1.5 mass %, and has a Vickers hardness of 220 Hv or more. 
     
     
         6 . The high strength copper alloy according to  claim 5 , wherein the high strength copper alloy is in a region B surrounded by four points of (Al: 4.0 mass %, Ni: 9.5 mass %), (Al: 7.0 mass %, Ni: 16.0 mass %), (Al: 2.5 mass %, Ni: 29.5 mass %), and (Al: 1.5 mass %, Ni: 14.0 mass %), as a range represented by Al equivalent (mass %)=(Al mass %+1.19Si mass %) and Ni mass %. 
     
     
         7 . The high strength copper alloy according to  claim 1 , wherein the high strength copper alloy further contains a total amount of 0.01 to 5.0 mass % of one or two or more elements selected from the group consisting of Co, Ti, Sn, Cr, Fe, Zr, Mg and Zn, as an addition element. 
     
     
         8 . The high strength copper alloy according to  claim 1 , wherein the high strength copper alloy further contains a total amount of 0.001 to 0.5 mass % of one or two or more elements selected from the group consisting of C, P and B, as an addition element. 
     
     
         9 . A process for producing the high strength copper alloy as defined in  claim 1 , comprising integrating, melting, mixing, hot-working and cold-working raw materials, then, heat-treating the worked product in a range of 700 to 1020° C. and 0.1 to 10 hours and, thereafter, aging-treating this in a range of 400 to 650° C., and 0.1 to 48 hours. 
     
     
         10 . The process for producing a high strength copper alloy according to  claim 9 , wherein before or after the aging treatment, cold working at a working ratio of 10 to 95% is performed.