HIGH STRENGTH Be/Cu ALLOYS WITH IMPROVED ELECTRICAL CONDUCTIVITY

Abstract

The electrical conductivity of a wrought processed, high strength, age hardened Be—Cu alloy is enhanced by overaging the alloy in manufacture.

1 . An aged hardened wrought Be/Cu alloy consisting essentially of about 1.60-2.00 wt. % Be, at least about 0.15 wt. % Co+Ni but no more than about 0.6 wt. % Co+Ni+Fe, optionally up to about 0.5 wt. % in total of Si, Al, Zr and Ti, the balance being copper and incidental impurities, the alloy having been overaged in manufacture. 
   
   
       2 . The alloy of  claim 1 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is greater by at least 3% IACS than the electrical conductivity of an otherwise identical alloy that has been peak aged in manufacture. 
   
   
       3 . The alloy of  claim 2 , wherein the amount of Be+Co+Ni+Fe+Cu in the alloy is at least 99.5 wt. %. 
   
   
       4 . The alloy of  claim 3 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is greater by at least 5% IACS than the electrical conductivity of the otherwise identical alloy 
   
   
       5 . The alloy of  claim 1 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is at least 28% IACS. 
   
   
       6 . The alloy of  claim 5 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is at least 30% IACS. 
   
   
       7 . The alloy of  claim 6 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is at least 33% IACS. 
   
   
       8 . The alloy of  claim 7 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is at least 35% IACS. 
   
   
       9 . The alloy of  claim 1 , wherein the alloy is in the form of a strip or stamped part. 
   
   
       10 . The alloy of  claim 9 , wherein the alloy is arranged in a closely-packed, bulk arrangement comprising either multiple revolutions of a continuous strip in a coil or multiple strip sections or stamped parts packed together in a side by side arrangement. 
   
   
       11 . The alloy of  claim 1 , wherein the alloy is made by the process comprising:
 (a) melting a composition containing the ingredients forming the alloy,   (b) casting the melt into a billet,   (c) hot rolling the billet into a strip,   (d) cold rolling the strip to a selected ready-to-finish thickness,   (e) final solution annealing the cold rolled strip at a temperature generally within a range of 1390° F. and 1500° F. followed by rapid quenching,   (f) optionally cold working the annealed strip, and   (g) overaging the cold worked strip to achieve an electrical conductivity of 30% IACS or more in the alloy product obtained.   
   
   
       12 . A process for increasing the electrical conductivity of a wrought, solution annealed, age hardenable Be/Cu alloy, the alloy consisting essentially of about 1.60-2.00 wt. % Be, at least about 0.15 wt. % Co+Ni but no more than about 0.6 wt. % Co+Ni+Fe, optionally up to about 0.5 wt. % in total of Si, Al, Zr and Ti, the balance being copper and incidental impurities, the process comprising overaging the alloy by an amount sufficient so that the electrical conductivity of the alloy produced is greater by at least 3% IACS than the electrical conductivity of an otherwise identical alloy peak aged during manufacture. 
   
   
       13 . The process of  claim 12 , wherein the amount of Be+Co+Ni+Fe+Cu in the alloy is at least 99.5 wt. %. 
   
   
       14 . The process of  claim 13 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is greater by at least 5% IACS than the electrical conductivity of the otherwise identical alloy 
   
   
       15 . The process of  claim 13 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is at least 28% IACS. 
   
   
       16 . The process of  claim 15 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is at least 30% IACS. 
   
   
       17 . The process of  claim 16 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is at least 33% IACS. 
   
   
       18 . The process of  claim 17 , wherein the alloy is overaged by an amount sufficient so that the electrical conductivity of the alloy is at least 35% IACS. 
   
   
       19 . The process of  claim 12 , wherein the alloy is in the form of a strip. 
   
   
       20 . The alloy of  claim 19 , wherein the strip is age hardened in a single age hardening step. 
   
   
       21 . The process of  claim 19 , wherein the strip is age hardened in multiple age hardening steps. 
   
   
       22 . The process of  claim 21 , wherein
 in at least one age hardening step, the alloy strip is arranged closely packed in bulk, wherein the alloy comprises either multiple strip sections or stamped parts arranged in a side by side relationship or multiple revolutions of a continuous alloy strip arranged in a coil, and   in at least one other age hardening step, multiple alloy sections of alloy strip or stamped parts are arranged in a non-closely packed arrangement.