Defect healing of deposited titanium alloys

Abstract

A method for treating a deposited titanium-base material from an initial condition to a treated condition includes a rapid heating and a rapid cooling. The heating is from a first temperature to a second temperature, the first temperature being below a β transus and the second temperature being below above the β transus. The cooling is from the second temperature to a third temperature below an equilibrium β transus.

1 . A method for treating a deposited titanium-base material from an initial condition to a treated condition comprising: 
 heating from a first temperature to a second temperature, the first temperature being below an equilibrium β transus, the second temperature being above the equilibrium β transus, and the heating including a portion at a rate in excess of 5° C./s; and    cooling from the second temperature to a third temperature below the equilibrium β transus.    
   
   
       2 . The method of  claim 1  wherein: 
 the heating is to a peak at least 10° C. above a non-equilibrium β transus; and    the material is above the equilibrium β transus for a period of no more than 2.0 seconds.    
   
   
       3 . The method of  claim 1  wherein: 
 the heating and cooling have sufficient rates to maintain a characteristic grain size of at least a matrix of the material smaller than 100 μm.    
   
   
       4 . The method of  claim 1  wherein: 
 in the initial condition, the material includes a plurality of defects having trunks with a microstructure distinct from a microstructure of a matrix of the material; and    in the treated condition, the trunks' microstructure have been essentially integrated with the matrix microstructure.    
   
   
       5 . The method of  claim 1  wherein: 
 the heating is to a peak 10-50° C. above a non-equilibrium β transus; and    the material is above the equilibrium β transus for a period of no more than 1.0 seconds.    
   
   
       6 . The method of  claim 1  wherein: 
 the heating is 1-30° C. above the equilibrium β transus for a period of 1.0-5.0 seconds; and    the cooling is sufficiently rapid to limit β growth to a characteristic size smaller than 100μm.    
   
   
       7 . The method of  claim 1  wherein: 
 the material consists in largest weight parts of titanium, aluminum, and vanadium; and    the material has a maximum thickness of at least 2.0 mm.    
   
   
       8 . The method of  claim 1  wherein: 
 the material is on a titanium-base substrate; and    the heating leaves essentially unaffected a microstructure of a major portion of the substrate.    
   
   
       9 . The method of  claim 1  wherein: 
 the heating is selected from the group consisting of direct resistance heating, induction heating, electron beam heating, and combinations thereof.    
   
   
       10 . The method of  claim 1  further comprising: 
 depositing the material on a titanium-base substrate.    
   
   
       11 . The method of  claim 10  wherein: 
 the depositing comprises electron beam physical vapor deposition.    
   
   
       12 . The method of  claim 10  wherein: 
 the material and the substrate consist essentially of an alloy of 5-7 weight percent aluminum, 3-5 weight percent vanadium, balance titanium, with less than 3 weight percent other components.    
   
   
       13 . The method of  claim 1  further comprising: 
 maintaining the material at a temperature of 500-660° C.    
   
   
       14 . The method of  claim 1  further comprising: 
 an annealing and aging step.    
   
   
       15 . The method of  claim 1  used to repair a gas turbine engine component having a titanium-base substrate.  
   
   
       16 . The method of  claim 15  further comprising: 
 operating the repaired component at a temperature in excess of 250° C.    
   
   
       17 . The method of  claim 1  wherein in the treated condition a laminar variation in at least a first alloy component is less than in the initial condition.  
   
   
       18 . A method for treating a deposited titanium-base material, the material initially having: 
 a matrix having first nominal chemistry and a first characteristic grain size and first characteristic grain structure;    a plurality of spits within the matrix and having: 
 a droplet having a higher level of refractory impurities than the matrix; and  
 a trunk extending from the droplet and having essentially the same chemistry as the matrix, but a larger second characteristic grain size and less equiaxed second grain structure,  
   the method comprising: 
 heating the material; and  
 cooling the material, the heating and cooling being sufficiently rapid to convert an α-β microstructure of the material to an essentially β-transformed microstructure, optionally including metastable martensite, and having a characteristic grain size smaller than 100 μm.  
   
   
   
       19 . The method of  claim 18  wherein: 
 the first nominal chemistry is essentially Ti-6Al-4V;    the second nominal chemistry is essentially Ti-6Al-4V; and    the material is atop an essentially Ti-6Al-4V substrate.    
   
   
       20 . The method of  claim 18  wherein: 
 at least some of the spits are further characterized by porosity adjacent their trunks; and    at least some of the porosity is healed.    
   
   
       21 . The method of  claim 18  wherein: 
 the droplets comprise at least 10% of one or a combination of refractory metals, by weight.    
   
   
       22 . The method of  claim 18  further comprising: 
 an annealing/aging step effective to essentially. eliminate the martensite.    
   
   
       23 . The method of  claim 18  wherein: 
 the material is a repair material on a turbine engine component.    
   
   
       24 . A component having: 
 a Ti-based metallic substrate; and    a Ti-based condensate atop the substrate and having: 
 a surface;  
 a plurality of embedded droplets below the surface;  
 regions directly between the droplets and the surface characterized by  
   an essentially β-transformed microstructure of a characteristic grain size below 100 μm.    
   
   
       25 . The component of  claim 24  wherein: 
 at least some of said droplets are at least 200 μm below the surface.    
   
   
       26 . The component of  claim 24  wherein: 
 at least some of said droplets are at least 20 μm in characteristic transverse dimension.    
   
   
       27 . The component of  claim 24  wherein: 
 at least some of said droplets comprise at least 20% Mo, by weight.    
   
   
       28 . The component of  claim 24  wherein: 
 the substrate and the condensate each consist essentially of Ti-6Al-4V.    
   
   
       29 . The component of  claim 24  being one of a gas turbine engine compressor blade, fan blade, disk, drum rotor, bearing housing, vane, and seal element.