beta titanium compositions and methods of manufacture thereof

Abstract

A composition comprises 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. 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 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.    
     
     
         2 . The composition of  claim 1 , wherein the composition is cold worked.  
     
     
         3 . The composition of  claim 2 , wherein the composition, after cold working, has an elastic recovery of greater than or equal to about 75% of the applied change in length when the applied change in length is 2% of the original length.  
     
     
         4 . The composition of  claim 2 , wherein the composition, after cold working, has an elastic recovery of greater than or equal to about 85% of the applied change in length when the applied change in length is 2% of the original length.  
     
     
         5 . The composition of  claim 2 , wherein the composition, after cold working, has an elastic recovery of greater than or equal to about 50% of the applied change in length when the applied change in length is 4% of the original length.  
     
     
         6 . The composition of  claim 2 , wherein the composition, after cold working, has an elastic recovery of greater than or equal to about 75% of the applied change in length when the applied change in length is 4% of the original length.  
     
     
         7 . The composition of  claim 2 , wherein the composition, after cold working, has a reduction in the elastic modulus of greater than or equal to about 10% when compared with the elastic modulus of an equivalent heat treated composition.  
     
     
         8 . The composition of  claim 2 , wherein the composition, after cold working, has a reduction in the elastic modulus of greater than or equal to about 20% when compared with the elastic modulus of an equivalent heat treated composition.  
     
     
         9 . The composition of  claim 2 , wherein the composition, after cold working, has a reduction in the elastic modulus of greater than or equal to about 25% when compared with the elastic modulus of an equivalent heat treated composition.  
     
     
         10 . The composition of  claim 1 , wherein the composition exhibits an elastic recovery of greater than or equal to about 50% of the applied change in length when the applied change in length is 4% of the original length.  
     
     
         11 . The composition of  claim 9 , wherein the composition has a β phase or an α phase and a β phase.  
     
     
         12 . The composition of  claim 11 , further comprising solution treating the composition.  
     
     
         13 . The composition of  claim 1 , wherein the composition is cold worked and shows an elastic recovery of greater than or equal to about 75% of the initial strain when elastically deformed to a 2% initial strain.  
     
     
         14 . The composition of  claim 1 , wherein the composition is cold worked and shows an elastic recovery of greater than or equal to about 50% of the initial strain when elastically deformed to a 4% initial strain.  
     
     
         15 . An article manufactured from the composition of  claim 1 .  
     
     
         16 . A composition comprising about 8.9 wt % molybdenum, about 3.03 wt % aluminum, about 1.95 wt % vanadium, about 3.86 wt % niobium, with the balance being titanium.  
     
     
         17 . The composition of  claim 16 , wherein the composition is cold worked.  
     
     
         18 . The composition of  claim 16 , having an elastic recovery of greater than or equal to about 75% of the applied change in length when the applied change in length is 2% of the original length.  
     
     
         19 . The composition of  claim 16 , having an elastic recovery of greater than or equal to about 50% of the applied change in length when the applied change in length is 4% of the original length.  
     
     
         20 . The composition of  claim 16 , wherein the composition, after cold working, has a reduction in the elastic modulus of greater than or equal to about 10% when compared with the elastic modulus of an equivalent heat treated composition.  
     
     
         21 . A composition comprising about 9.34 wt % molybdenum, about 3.01 wt % aluminum, about 1.95 wt % vanadium, about 3.79 wt % niobium, with the balance being titanium.  
     
     
         22 . The composition of  claim 21 , wherein the composition is cold worked.  
     
     
         23 . The composition of  claim 21 , having an elastic recovery of greater than or equal to about 50% of the applied change in length when the applied change in length is 4% of the original length.  
     
     
         24 . The composition of  claim 21 , having an elastic recovery of greater than or equal to about 75% of the applied change in length when the applied change in length is 2% of the original length.  
     
     
         25 . The composition of  claim 21 , wherein the composition, after cold working, has a reduction in the elastic modulus of greater than or equal to about 10% when compared with the elastic modulus of an equivalent heat treated composition.  
     
     
         26 . A method for making an article comprising:. 
 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.    
     
     
         27 . The method of  claim 26 , wherein the solution heat treating is conducted at a temperature below the isomorphic temperature for the composition.  
     
     
         28 . The method of  claim 26 , wherein the solution heat treating is conducted at a temperature above the isomorphic temperature for the composition.  
     
     
         29 . The method of  claim 26 , wherein the cooling is conducted in air.  
     
     
         30 . The method of  claim 26 , wherein the shape is further heat aged at a temperature of about 350 to about 550° C.  
     
     
         31 . The method of  claim 30 , wherein the heat ageing is conducted for a time period of 10 seconds to about 30 minutes.  
     
     
         32 . A method comprising: 
 cold working a wire having 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 treating the wire; and    heat treating the wire.    
     
     
         33 . The method of  claim 32 , wherein the cold working results in a reduction in cross-sectional area of about 5 to about 85%.  
     
     
         34 . The method of  claim 32 , wherein the wire diameter is about 0.1 to about 10 millimeters.  
     
     
         35 . The method of  claim 32 , wherein the heat treating is conducted at a temperature of about 500° C. to about 900° C.  
     
     
         36 . The method of  claim 32 , wherein the wire is solution treated at a temperature of about 800 to about 1000° C.  
     
     
         37 . The method of  claim 32 , wherein the article has a β phase or an α phase and a β phase.  
     
     
         38 . The method of  claim 32 , wherein the article has an elastic recovery of greater than or equal to about 75% of the applied change in length when the applied change in length is 2% of the original length.  
     
     
         39 . The method of  claim 32 , wherein the article has an elastic recovery of greater than or equal to about 50% of the applied change in length when the applied change in length is 4% of the original length.