Method for manufacturing titanium alloy wire with enhanced properties

Abstract

A method for producing reinforced titanium alloy wire, comprising forming a billet of titanium alloy with grains of a precipitated discontinuous reinforcement material such as TiB and/or TiC. The billet may be formed by the hot consolidation of a titanium alloy powder formed by gas atomization. The billet is then hot formed to reduce it to rod or coil form. The rod or coil is then subjected to successive cold drawing operations to form a reinforced titanium alloy wire of reduced diameter. The cold drawing includes periodic annealing operations under low oxygen conditions to relieve work hardening and to recrystallize the reinforcement material grains to reduce the size thereof.

1 . A method for producing reinforced titanium alloy wire, comprising: 
 forming a billet of titanium alloy with grains of a precipitated discontinuous reinforcement material;    hot forming the billet to reduce it to rod or coil form; and    cold drawing the rod or coil in successive operations to wire of reduced diameter, said cold drawing including the periodic annealing of the wire under low oxygen conditions to relieve work hardening and to recrystallize the reinforcement material grains to reduce the size thereof.    
   
   
       2 . The method of  claim 1  wherein said billet is hot forged to create a uniform chemistry and microstructure before it is hot formed.  
   
   
       3 . The method of  claim 1  wherein said reinforcement material is TiB.  
   
   
       4 . The method of  claim 3  wherein said billet is cast from a Boron rich melt.  
   
   
       5 . The method of  claim 3  wherein said billet is formed by consolidating titanium alloy powder formed by gas atomization from a Boron rich melt.  
   
   
       6 . The method of  claim 5  wherein said powder is gas atomized powder with a composition of Ti-6Al-4V-1.7B in a size range of minus 35 mesh to plus 270 mesh, with an interstitial content of oxygen less than 1500 ppm.  
   
   
       7 . The method of  claim 1  wherein said reinforcement material is TiC.  
   
   
       8 . The method of  claim 1  wherein said reinforcement material is TiB and TiC.  
   
   
       9 . The method of  claim 5  wherein said consolidating is by hot isostatic pressing at a pressure of approximately 15,000 psi and a temperature of approximately 1650° F. to 1750° F.  
   
   
       10 . The method of  claim 1  wherein said titanium alloy is Ti-6Al-4V.  
   
   
       11 . The method of  claim 1  wherein said titanium alloy is Ti-6Al-2Sn-4Zr-2Mo.  
   
   
       12 . The method of  claim 1  wherein said hot forming is at a temperature of approximately 1750° F.  
   
   
       13 . The method of  claim 12  wherein said hot forming results in about a 50:1 hot reduction in section area to break up and reduce the size of the reinforcement material grains.  
   
   
       14 . The method of  claim 1  wherein said cold drawing is performed periodically to reduce the size of the wire at a rate of approximately 10 percent for each drawing operation during the first half of the desired diameter reduction.  
   
   
       15 . The method of  claim 14  wherein the rate of reduction is increased to approximately 15 percent at the midpoint of diameter reduction and to approximately 20 percent near the end of the diameter reduction.  
   
   
       16 . The method of  claim 1  wherein said annealing is performed at intervals corresponding to an accumulated reduction of wire diameter of about 50 percent for about 1 hour in inert gas with forced inert gas cooling.  
   
   
       17 . A method for producing reinforced titanium alloy wire, comprising: 
 forming a powder of titanium alloy by gas atomization from a Boron rich melt;    consolidating the titanium alloy powder under heat and pressure into a billet having grains of precipitated discontinuous TiB reinforcement;    hot forming the billet to reduce it to rod or coil form and to break up and reduce the size of the TiB grains;    cold drawing the rod or coil in successive operations to wire of reduced diameter, said cold drawing including the periodic annealing of the wire under low oxygen conditions to relieve work hardening and to recrystallize the TiB grains to reduce the size thereof.    
   
   
       18 . The method of  claim 17  wherein said powder is gas atomized powder with a composition of Ti-6Al-4V-1.7B in a size range of minus 35 mesh to plus 270 mesh, with an interstitial content of oxygen less than 1500 ppm.  
   
   
       19 . The method of  claim 17  wherein said titanium alloy is Ti-6Al-4V.  
   
   
       20 . The method of  claim 17  wherein said titanium alloy is Ti-6Al-2Sn-4Zr-2Mo.  
   
   
       21 . The method of  claim 17  wherein said consolidating is by hot isostatic pressing at a pressure of approximately 15,000 psi and a temperature of approximately 1650° F. to 1750° F.  
   
   
       22 . The method of  claim 17  wherein said hot forming is at a temperature of approximately 1750° F.  
   
   
       23 . The method of  claim 22  wherein said hot forming results in about a 50:1 hot reduction in section area to break up and reduce the size of the reinforcement material grains.  
   
   
       24 . The method of  claim 17  wherein said cold drawing is performed periodically to reduce the size of the wire at a rate of approximately 10 percent for each drawing operation during the first half of the desired diameter reduction.  
   
   
       25 . The method of  claim 24  wherein the rate of reduction is increased to approximately 15 percent at the midpoint of diameter reduction and to approximately 20 percent near the end of the diameter reduction.  
   
   
       26 . The method of  claim 17  wherein said annealing is performed at intervals corresponding to an accumulated reduction of wire diameter of about 50 percent for about 1 hour in inert gas with forced inert gas cooling.