System and method for thermal forming with active cooling and parts formed thereby

Abstract

A method for thermal forming includes determining a process window for initiating cooling, locally heating at least one region on a specimen to achieve a pre-selected geometry deformation, initiating active cooling of the heated region within the process window to control at least one material property of the specimen at the heated region and actively cooling the heated region to a pre-selected temperature. A system for thermal forming includes a thermal source for heating the region on the specimen to achieve a pre-selected geometry deformation, an active cooling module for cooling the region to a pre-selected temperature and a control module to control at least one of the thermal source and active cooling module in accordance with a process window to initiate active cooling to control at least one material property of the specimen at the heated region. The process window has an upper time limit for initiating cooling.

1 . A method for thermal forming comprising: 
 determining a process window for initiation of a cooling process;    locally heating at least one region on a specimen to achieve a pre-selected geometry deformation;    initiating active cooling of the heated region within the process window to control at least one material property of the specimen at the heated region; and    actively cooling the heated region to a pre-selected temperature.    
   
   
       2 . The method of  claim 1 , wherein the material property comprises microhardness.  
   
   
       3 . The method of  claim 2 , wherein the microhardness is controlled to within about three standard deviations of a mean initial hardness.  
   
   
       4 . The method of  claim 1 , wherein the specimen comprises a precipitation-strengthened alloy.  
   
   
       5 . The method of  claim 4 , wherein the precipitation-strengthened alloy comprises a plurality of precipitates prior to said heating step, wherein the process window comprises an upper time limit for initiation of the cooling process, and wherein the upper limit is selected such that the precipitates are substantially maintained in the heated region of the specimen.  
   
   
       6 . The method of  claim 4 , wherein the precipitation-strengthened alloy comprises a nickel-based alloy.  
   
   
       7 . The method of  claim 6 , wherein the nickel-based alloy comprises a volume fraction of a γ″ phase prior to said heating step, wherein the process window comprises an upper time limit for initiation of the cooling process, and wherein the upper limit is selected such that the volume fraction of the γ″ phase is substantially maintained for the heated region of the specimen.  
   
   
       8 . The method of  claim 6 , wherein the nickel-based alloy comprises UNS 07718 alloy.  
   
   
       9 . The method of  claim 1 , wherein the specimen comprises a titanium alloy.  
   
   
       10 . The method of  claim 9 , wherein the titanium alloy comprises a volume fraction of an α phase prior to said heating step, wherein the process window comprises an upper time limit for initiation of the cooling process, and wherein the upper limit is selected such that a discontinuity of a prior beta grain boundary alpha phase is substantially maintained for the heated region of the specimen.  
   
   
       11 . The method of  claim 1 , wherein the process window comprises an upper time limit and a lower time limit for initiation of the cooling process.  
   
   
       12 . The method of  claim 11 , wherein said determining the process window comprises determining at least one of the upper and lower time limits using experimental data.  
   
   
       13 . The method of  claim 12 , wherein the upper limit is determined using experimental data.  
   
   
       14 . The method of  claim 11 , wherein said determining the process window comprises determining at least one of the upper and lower time limits using simulation data.  
   
   
       15 . The method of  claim 1 , wherein said heating step comprises laser heating the at least one region.  
   
   
       16 . A system for thermal forming comprising: 
 a thermal source configured for heating at least one region on a specimen to achieve a pre-selected geometry deformation;    an active cooling module configured for cooling the heated region to a pre-selected temperature; and    a control module configured to control at least one of said thermal source and said active cooling module in accordance with a process window in order to initiate active cooling of the heated region by said active cooling module within the process window to control at least one material property of the specimen at the heated region, wherein the process window comprises an upper time limit for initiation of the cooling.    
   
   
       17 . The system of  claim 16 , wherein said thermal source comprises a laser.  
   
   
       18 . The system of  claim 16 , wherein said control module is configured to control both of said thermal source and said active cooling module in accordance with the processing window.  
   
   
       19 . The system of  claim 16 , further comprising an algorithm module configured to determine the process window for initiating active cooling.  
   
   
       20 . The system of  claim 19 , wherein the specimen comprises a precipitation-strengthened alloy, wherein the precipitation-strengthened alloy comprises a plurality of precipitates prior to heating by said thermal source, and wherein said algorithm module is configured to determine the upper time limit such that the precipitates are substantially maintained in the heated region of the specimen.  
   
   
       21 . The system of  claim 19 , wherein the specimen comprises a nickel-based alloy, wherein the nickel based alloy comprises a volume fraction of a γ″ phase prior to heating by said thermal source, and wherein said algorithm unit is configured to determine the upper time limit such that the volume fraction of the γ″ phase is substantially maintained for the heated region of the specimen.  
   
   
       22 . The system of  claim 19 , wherein the specimen comprises a titanium alloy, wherein the titanium alloy comprises a volume fraction of an α phase prior to heating by said thermal source, and wherein said algorithm unit is configured to determine the upper time limit such that the volume fraction of the α phase is substantially maintained for the heated region of the specimen.  
   
   
       23 . The system of  claim 19 , wherein the process window further comprises a lower time limit for initiation of the cooling.  
   
   
       24 . The system of  claim 16 , wherein said active cooling module comprises a liquid bath configured to receive the specimen.  
   
   
       25 . The system of  claim 16 , wherein said active cooling module comprises a liquid spray source configured for spray cooling the specimen.  
   
   
       26 . The system of  claim 16 , wherein said active cooling module comprises a gas spray source configured for spray cooling the specimen.  
   
   
       27 . The system of  claim 16 , wherein said active cooling module comprises a fluidized particle bed configured to receive the specimen.  
   
   
       28 . The system of  claim 16 , wherein said active cooling module comprises an initially solid coolant configured to receive the specimen.  
   
   
       29 . A part comprising an alloy and at least one thermally formed region, wherein the alloy comprises a volume fraction of a first phase prior to laser forming, and wherein the volume fraction of the first phase is substantially maintained for the thermally formed region.  
   
   
       30 . The part of  claim 29 , wherein the alloy comprises a nickel-based alloy, and wherein the first phase comprises a γ″ phase.  
   
   
       31 . The part of  claim 30 , wherein the nickel-based alloy comprises UNS 07718 alloy.  
   
   
       32 . The part of  claim 29 , wherein the alloy comprises a titanium alloy, and wherein the first phase comprises an α phase.  
   
   
       33 . The part of  claim 29 , wherein the part is selected from the group consisting of airfoils, blades, disks, blisks, combustors, plates, flanges, ducts, and tubes.