Method and apparatus for forming and heat treating structural assemblies

Abstract

There are provided an apparatus and an associated method for manufacturing superplastically formed structural assemblies from preforms. The apparatus includes first and second co-operable dies structured to define a die cavity therebetween for at least partially receiving the preform, at least one heater in thermal communication with the die cavity for heating the preform to a forming temperature, and at least one injector in fluid communication with the die cavity. The injector is structured for injecting pressurized gas into the die cavity to urge the preform against one of the dies to form the preform into the structural assembly. Further, at least one of the injectors is structured for injecting a quenchant into the die cavity to thereby heat treat the structural assembly while distortion of the structural assembly is being at least partially restrained by at least one of the dies.

1 . An apparatus for forming a structural assembly from at least one preform, comprising: 
 first and second co-operable dies structured to define a die cavity therebetween for at least partially receiving the at least one preform;    at least one heater in thermal communication with said die cavity for heating the at least one preform to a forming temperature; and    at least one injector in fluid communication with said die cavity, wherein at least one of said at least one injector is structured for injecting pressurized gas into said die cavity to urge the at least one preform at least partially against at least one of said first and second dies to thereby form the at least one preform into the structural assembly, and wherein at least one of said at least one injector is structured for injecting a quenchant into said die cavity to thereby heat treat the structural assembly while distortion of the structural assembly is being at least partially restrained by at least one of said first and second dies.    
     
     
         2 . An apparatus according to  claim 1  wherein said at least one injector for injecting a quenchant comprises a tubular member comprising a plurality of nozzles structured to spray said quenchant onto the structural assembly.  
     
     
         3 . An apparatus according to  claim 1  further comprising a valve in fluid communication with said die cavity, said valve being structured to maintain the pressure within said die cavity below a predetermined pressure; and 
 wherein said at least one injector for injecting a quenchant comprises a tubular member defining a plurality of apertures in fluid communication with said valve.    
     
     
         4 . An apparatus according to  claim 1 , further comprising at least one drain connected to said die cavity for conveying fluid from said die cavity.  
     
     
         5 . An apparatus according to  claim 1  further comprising a sealing frame having first and second portions, said first portion of said sealing frame being attached to said first die, said second portion of said sealing frame being attached to said second die, and wherein said first and second portions of said sealing frame are structured to at least partially engage the at least one preform so as to seal said die cavity.  
     
     
         6 . An apparatus according to  claim 5  wherein said at least one injector for injecting a quenchant is sealably attached to at least one of said first and second portions of said sealing frame.  
     
     
         7 . An apparatus according to  claim 1  further comprising at least one susceptor and wherein said at least one heater comprises at least one induction coil structured to induce an electromagnetic field within at least a portion of said at least one susceptor.  
     
     
         8 . An apparatus according to  claim 7  wherein said at least one susceptor has a Curie temperature at which said at least one susceptor becomes paramagnetic.  
     
     
         9 . An apparatus according to  claim 8  wherein the Curie temperature of said at least one susceptor is about equal to the forming temperature of the at least one preform.  
     
     
         10 . An apparatus according to  claim 1  wherein at least one of said first and second dies comprises at least one sensor for measuring at least one of the temperature and pressure inside said die cavity.  
     
     
         11 . An apparatus for forming a structural assembly from at least one preform, comprising: 
 first and second co-operable dies structured to define a die cavity therebetween for at least partially receiving the at least one preform, at least one of said first and second dies defining a forming surface for shaping the at least one preform into the structural assembly;    at least one heater in thermal communication with said die cavity for heating the at least one preform to a forming temperature; and    at least one injector in fluid communication with said die cavity, wherein at least one of said at least one injector is structured for injecting pressurized gas into said die cavity to pressurize said die cavity and to urge the at least one preform at least partially against said forming surface of at least one of said first and second dies to form the at least one preform into the structural assembly, and wherein at least one of said at least one injector is structured for injecting a quenchant into said die cavity to thereby heat treat the structural assembly while the structural assembly is being urged at least partially against said forming surface of at least one of said first and second dies to thereby reduce distortion of the structural assembly.    
     
     
         12 . An apparatus according to  claim 11  wherein said at least one injector for injecting a quenchant comprises a tubular member comprising a plurality of nozzles structured to spray said quenchant onto the structural assembly.  
     
     
         13 . An apparatus according to  claim 11  further comprising a valve in fluid communication with said die cavity, said valve being structured to maintain the pressure within said die cavity below a predetermined pressure; and 
 wherein said at least one injector for injecting a quenchant comprises a tubular member defining a plurality of apertures in fluid communication with said valve.    
     
     
         14 . An apparatus according to  claim 11  wherein at least one of said first and second dies defines at least one aperture in fluid communication with said die cavity, said aperture being structured to drain said quenchant from said die cavity.  
     
     
         15 . An apparatus according to  claim 11  further comprising a sealing frame having first and second portions, said first portion being attached to said first die, said second portion being attached to said second die, and wherein said first and second portions of said sealing frame are structured to at least partially engage the at least one preform so as to seal said die cavity.  
     
     
         16 . An apparatus according to  claim 15  wherein said at least one injector for injecting a quenchant is sealably attached to at least one of said first and second portions of said sealing frame.  
     
     
         17 . An apparatus according to  claim 11  further comprising at least one susceptor and wherein said at least one heater comprises at least one induction coil structured to induce an electromagnetic field within at least a portion of said susceptor.  
     
     
         18 . An apparatus according to  claim 17  wherein said at least one susceptor has a Curie temperature at which said at least one susceptor becomes paramagnetic.  
     
     
         19 . An apparatus according to  claim 18  wherein the Curie temperature of said at least one susceptor is about equal to the forming temperature of the at least one preform.  
     
     
         20 . An apparatus according to  claim 11  wherein at least one of said first and second dies comprises at least one sensor for measuring at least one of the temperature and pressure inside said die cavity.  
     
     
         21 . A method of manufacturing a structural assembly, comprising: 
 forming at least one preform against at least one of first and second dies to form the preform into the structural assembly; and    aging the structural assembly according to a predetermined aging schedule and concurrently at least partially restraining distortion of the structural assembly using at least one of the first and second co-operable dies.    
     
     
         22 . A method according to  claim 21  wherein said forming step comprises heating the at least one preform to a forming temperature and injecting pressurized gas at least partially against the at least one preform so as to urge the at least one preform at least partially against at least one of the first and second dies to thereby form the structural assembly.  
     
     
         23 . A method according to  claim 22  wherein said heating step comprises energizing at least one induction coil to induce an electromagnetic field in at least one susceptor.  
     
     
         24 . A method according to  claim 23  wherein said heating step comprises heating the at least one susceptor to the Curie temperature of the at least one susceptor.  
     
     
         25 . A method according to  claim 21  wherein said aging step comprises heating the structural assembly according to a predetermined temperature schedule by energizing at least one induction coil to induce an electromagnetic field in at least one susceptor.  
     
     
         26 . A product obtained by the method of  claim 21 .  
     
     
         27 . A product according to  claim 26  wherein the structural assembly is formed of at least one of the group consisting of aluminum and aluminum alloys.  
     
     
         28 - 40 . (canceled)