Copper base alloy

Abstract

This invention has for an object thereof the provision of a leadless copper-based alloy which mends the deterioration of tensile strength at elevated temperatures and enables the mechanical properties thereof to approximate the CAC406 by forming in the alloy texture thereof an alloy or an intermetallic compound with Bi and Pb existing independently or in a mutually joined state. For the purpose of accomplishing the object, this invention incorporates in the copper-based alloy an additive element capable of forming an alloy or an intermetallic compound with Bi and Pb existing independently or in a mutually joined state. The additive element is one or more members selected from the group consisting of Te, P, Zr, Ti, Co, In, Ca, B and misch metal.

1 - 7 . (canceled)  
     
     
         8 . A copper-based alloy containing Bi and Pb and having 0.01 to 1.0 weight % of Te incorporated therein as an additive element to form in an alloy texture an intermetallic compound of Pb—Te having a higher melting point than a Bi—Pb binary eutectic crystal, suppress occurrence of the Bi—Pb binary eutectic crystal in the alloy texture and improve mechanical properties, particularly tensile strength, thereof at elevated temperatures.  
     
     
         9 . A copper-based alloy according to claim  1 , wherein the additive element is contained in a ratio of 0.01 to 0.22 weight %.  
     
     
         10 . A copper-based alloy according to claim  1 , wherein it contains at least Sn in a ratio of 2.8 to 6.0 weight %, Zn in a ratio of 1.0 to 12.0 weight % and Bi in a ratio of 0.1 to 3.0 weight %.  
     
     
         11 . A copper-based alloy according to claim  3 , wherein it contains at least Sn in a ratio of 2.8 to 6.0 weight %, Zn in a ratio of 1.0 to 12.0 weight % and Bi in a ratio of 0.1 to 3.0 weight %.  
     
     
         12 . A copper-based alloy according to claim  1 , wherein it contains at least Sn in a ratio of 2.8 to 6.0 weight %, Zn in a ratio of 1.0 to 12.0 weigh %, Bi in a ratio of 0.1 to 2.4 weight % and Se in a radio of 0.05 to 1.2 weight %.  
     
     
         13 . A copper-based alloy according to claim  3 , wherein it contains at least Sn in a ratio of 2.8 to 6.0 weight%, Zn in a ratio of 1.0 to 12.0 weigh%, Bi in a ratio of 0.1 to 2.4 weight% and Se in a radio of 0.05 to 1.2 weight %.  
     
     
         14 . A copper-based alloy according to  claim 8 , wherein it has a Pb content of not more than 0.25 weight %.  
     
     
         15 . A copper-based alloy according to  claim 9 , wherein it has a Pb content of not more than 0.25 weight %.  
     
     
         16 . A copper-based alloy according to  claim 10 , wherein it has a Pb content of not more than 0.25 weight %.  
     
     
         17 . A copper-based alloy according to  claim 11 , wherein it has a Pb content of not more than 0.25 weight %.  
     
     
         18 . A copper-based alloy according to  claim 12 , wherein it has a Pb content of not more than 0.25 weight %.  
     
     
         19 . A copper-based alloy according to  claim 13 , wherein it has a Pb content of not more than 0.25 weight %.