Beta titanium compositions and methods of manufacture thereof

Abstract

A composition comprises about 8 to about 12 wt % molybdenum, about 2.8 to about 6 wt % aluminum, up to about 2 wt % vanadium, up to about 4 wt % niobium, with the balance being titanium, wherein the weight percents are based on the total weight of the alloy composition. A method for making an article comprises cold-working a shape from a composition comprising about 8 to about 10 wt % molybdenum, about 2.8 to about 6 wt % aluminum, up to about 2 wt % vanadium, up to about 4 wt % niobium, with the balance being titanium, wherein the weight percents are based on the total weight of the alloy composition; solution heat treating the shape; and cooling the shape.

What is claimed is:  
     
         1 . A method for producing an alloy composition comprising: 
 annealing the alloy composition; and    deforming the alloy composition at a temperature greater than ambient temperature to a temperature below that at which (x and w phase precipitates are formed; wherein the composition comprises titanium; and a molybdenum equivalent weight of about 7 to about 11 wt %, wherein the weight percents are based upon the total weight of the alloy composition.    
     
     
         2 . The method of  claim 1 , wherein the molybdenum equivalent weight is determined by the equation (1)  
       Mo eq. =1.00Mo+0.28Nb+0.22Ta+0.67V+1.43Co+1.60Cr+0.77Cu+2.9OFe+1.54Mn+1.11Ni+0.44W−1.00Al   (1)  
       or the equation (2)  
       Mo eq. =1.00Mo+0.28Nb+0.22Ta+0.67V+1.43Co+1.60Cr+0.77Cu+2.9OFe+1.54Mn+1.11Ni+0.44W+0.25(Sn+Zr+Hf)−1.00Al   (2)  
       wherein Mo is molybdenum, Nb is niobium, Ta is tantalum, V is vanadium, Co is cobalt, Cr is chromium, Cu is copper, Fe is iron, Mn is manganese, Ni is nickel, W is tungsten, Al is aluminum, Sn is tin, Zr is zirconium and Hf is hafnium; wherein aluminum can be substituted by gallium, carbon, germanium and/or boron; and wherein the respective chemical symbols represent the amounts of the respective elements in weight percent based on the total weight of the alloy composition.  
     
     
         3 . The method of  claim 1 , wherein the alloy composition comprises: 
 about 8 to about 12 wt % molybdenum,    about 2.8 to about 6 wt % aluminum,    up to about 2 wt % vanadium,    up to about 4 wt % niobium, with the balance being titanium, wherein the weight percents are based on the total weight of the alloy composition.    
     
     
         4 . The method of  claim 1 , wherein the annealing is conducted at a temperature of about 800 to about 900° C.  
     
     
         5 . The method of  claim 1 , wherein the deforming is conducted at a temperature of about 50 to about 400° C.  
     
     
         6 . The method of  claim 1 , wherein the composition has an elastic modulus of 10% less than the elastic modulus of a similar composition that has been annealed but not subjected to the deforming of a forming operation.  
     
     
         7 . The method of  claim 1 , wherein the composition has an elastic modulus of 20% less than the elastic modulus of a similar composition that has been annealed but not subjected to the deforming of a forming operation.  
     
     
         8 . The method of  claim 1 , wherein the alloy composition has a β phase and/or an α and a β phase.  
     
     
         9 . A method for manufacturing an alloy composition having a high fatigue resistance comprising: 
 annealing the alloy composition; and    cold working the alloy composition; wherein the composition comprises wherein the composition comprises titanium; and a molybdenum equivalent weight of about 7 to about 11 wt %, wherein the weight percents are based upon the total weight of the alloy composition.    
     
     
         10 . The method of  claim 9 , wherein the molybdenum equivalent weight is determined by the equation (1)  
       Mo eq. =1.00Mo+0.28Nb+0.22Ta+0.67V+1.43Co+1.60Cr+0.77Cu+2.90Fe+1.54Mn+1.11Ni+0.44W−1.00Al   (1)  
       or the equation (2)  
       Mo eq. =1.00Mo+0.28Nb+0.22Ta+0.67V+1.43Co+1.60Cr+0.77Cu+2.90Fe+1.54Mn+1.11Ni+0.44W+0.25(Sn+Zr+Hf)−1.00Al   (2)  
       wherein Mo is molybdenum, Nb is niobium, Ta is tantalum, V is vanadium, Co is cobalt, Cr is chromium, Cu is copper, Fe is iron, Mn is manganese, Ni is nickel, W is tungsten, Al is aluminum, Sn is tin, Zr is zirconium and Hf is hafnium; wherein aluminum can be substituted by gallium, carbon, germanium and/or boron; and wherein the respective chemical symbols represent the amounts of the respective elements in weight percent based on the total weight of the alloy composition.  
     
     
         11 . The method of  claim 9 , wherein the alloy composition comprises: 
 about 8 to about 12 wt % molybdenum,    about 2.8 to about 6 wt % aluminum,    up to about 2 wt % vanadium,    up to about 4 wt % niobium, with the balance being titanium, wherein the weight percents are based on the total weight of the alloy composition.    
     
     
         12 . The method of  claim 9 , wherein the cold working comprises a reduction in the cross-sectional area of greater than or equal to about 10 percent.  
     
     
         13 . The method of  claim 9 , wherein the annealing is conducted at a temperature of about 800 to about 900° C.  
     
     
         14 . The method of  claim 9 , wherein the alloy composition has a fatigue resistance exceeding 10 million cycles at 0.75% bend strain.  
     
     
         15 . An alloy composition comprising: 
 titanium; and    a molybdenum equivalent weight of about 7 to about 11 wt %, wherein the weight percents are based upon the total weight of the alloy composition; wherein the composition is subjected to a process comprising annealing and deformation at a temperature greater than ambient temperature to a temperature below that at which a and ω phase precipitates are formed.    
     
     
         16 . The composition of  claim 15 , wherein the molybdenum equivalent weight is determined by the equation (1)  
       Mo eq. =1.00Mo+0.28Nb+0.22Ta+0.67V+1.43Co+1.60Cr+0.77Cu+2.90Fe+1.54Mn+1.11Ni+0.44W−1.00Al   (1)  
       or the equation (2)  
       Mo eq. =1.00Mo+0.28Nb+0.22Ta+0.67V+1.43Co+1.60Cr+0.77Cu+2.90Fe+1.54Mn+1.11Ni+0.44W+0.25(Sn+Zr+Hf)−1.00Al   (2)  
       wherein Mo is molybdenum, Nb is niobium, Ta is tantalum, V is vanadium, Co is cobalt, Cr is chromium, Cu is copper, Fe is iron, Mn is manganese, Ni is nickel, W is tungsten, Al is aluminum, Sn is tin, Zr is zirconium and Hf is hafnium; wherein aluminum can be substituted by gallium, carbon, germanium and/or boron; and wherein the respective chemical symbols represent the amounts of the respective elements in weight percent based on the total weight of the alloy composition.  
     
     
         17 . The composition of  claim 15 , wherein the alloy composition comprises: 
 about 8 to about 12 wt % molybdenum,    about 2.8 to about 6 wt % aluminum,    up to about 2 wt % vanadium,    up to about 4 wt % niobium, with the balance being titanium, wherein the weight percents are based on the total weight of the alloy composition.    
     
     
         18 . An alloy composition comprising: 
 titanium; and    a molybdenum equivalent weight of about 7 to about 11 wt %, wherein the weight percents are based upon the total weight of the alloy composition; wherein the composition is subjected to a process comprising annealing and cold working.    
     
     
         19 . The composition of  claim 18 , wherein the molybdenum equivalent weight is determined by the equation (1)  
       Mo eq. =1.00Mo+0.28Nb+0.22Ta+0.67V+1.43Co+1.60Cr+0.77Cu+2.90Fe+1.54Mn+1.11Ni+0.44W−1.00Al   (1)  
       or the equation (2)  
       Mo eq. =1.00Mo+0.28Nb+0.22Ta+0.67V+1.43Co+1.60Cr+0.77Cu+2.90Fe+1.54Mn+1.11Ni+0.44W+0.25(Sn+Zr+Hf)−1.00Al   (2)  
       wherein Mo is molybdenum, Nb is niobium, Ta is tantalum, V is vanadium, Co is cobalt, Cr is chromium, Cu is copper, Fe is iron, Mn is manganese, Ni is nickel, W is tungsten, Al is aluminum, Sn is tin, Zr is zirconium and Hf is hafnium; wherein aluminum can be substituted by gallium, carbon, germanium and/or boron; and wherein the respective chemical symbols represent the amounts of the respective elements in weight percent based on the total weight of the alloy composition.  
     
     
         20 . The composition of  claim 18 , wherein the alloy composition comprises: 
 about 8 to about 12 wt % molybdenum,    about 2.8 to about 6 wt % aluminum,    up to about 2 wt % vanadium,    up to about 4 wt % niobium, with the balance being titanium, wherein the weight percents are based on the total weight of the alloy composition.    
     
     
         21 . An article manufactured by the method of  claim 1 .  
     
     
         22 . An article manufactured by the method of  claim 11 .  
     
     
         23 . An article manufactured by the composition of  claim 15 .  
     
     
         24 . An article manufactured by the composition of  claim 18.