Method of forming non-sag molybdenum-lanthana alloys

Abstract

A method for forming a molybdenum-lanthana alloy is described wherein a non-sag microstructure is achieved by mechanically working an as-sintered or recrystallized body to obtain a degree of deformation of from about 7% to about 18% and then subjecting the lightly worked body to a final recrystallization.

1 . A method for forming a non-sag molybdenum-lanthana alloy comprising: 
 (a) forming a sintered body of a molybdenum-lanthana alloy wherein the alloy contains from about 0.1 weight percent to about 5 weight percent lanthana;    (b) mechanically working the sintered body to a near-finished form;    (c) recrystallizing the sintered body in its near-finished form;    (d) mechanically deforming the sintered body to a finished form wherein the degree of deformation is from about 7% to about 18%; and    (e) subjecting the sintered body in its finished form to a final recrystallization annealing.    
     
     
         2 . The method of  claim 1  wherein the degree of deformation is from about 12% to about 17%.  
     
     
         3 . The method of  claim 1  wherein the final recrystallization annealing is performed at about 1900° C.  
     
     
         4 . The method of  claim 1  wherein the sintered body in its near-finished form is recrystallized at a temperature from about 1150° C. to about 1400° C.  
     
     
         5 . The method of  claim 1  wherein the molybdenum-lanthana alloy contains from about 0.4 weight percent to about 1.0 weight percent lanthana.  
     
     
         6 . The method of claim  1 .wherein the sintered body is subjected to one or more heat treatments during the mechanical working in step (b).  
     
     
         7 . The method of  claim 3  wherein the molybdenum-lanthana alloy contains from about 0.6 weight percent to about 0.7 weight percent lanthana.  
     
     
         8 . A method for forming a non-sag molybdenum-lanthana alloy comprising: 
 (a) forming a sintered body of a molybdenum-lanthana alloy wherein the alloy contains from about 0.4 weight percent to about 1.0 weight percent lanthana;    (b) mechanically working the sintered body to a near-finished form;    (c) recrystallizing the sintered body in its near-finished form at a temperature from about 1150° C. to about 1400° C.;    (d) mechanically deforming the sintered body to a finished form wherein the degree of deformation is from about 7% to about 18%; and    (e) subjecting the sintered body in its finished form to a final recrystallization annealing at a temperature of about 1900° C.    
     
     
         9 . The method of  claim 8  wherein the degree of deformation is from about 12% to about 17%.  
     
     
         10 . The method of  claim 8  wherein the molybdenum-lanthana alloy contains from about 0.6 weight percent to about 0.7 weight percent lanthana.  
     
     
         11 . A method for forming a non-sag molybdenum-lanthana alloy comprising: 
 (a) forming a sintered body of a molybdenum-lanthana alloy wherein the alloy contains from about 0.1 weight percent to about 5 weight percent lanthana;    (b) mechanically deforming the sintered body to a finished form wherein the degree of deformation is from about 7% to about 18%; and    (c) subjecting the sintered body in its finished form to a final recrystallization annealing.    
     
     
         12 . The method of  claim 11  wherein the degree of deformation is from about 12% to about 17%.  
     
     
         13 . The method of  claim 11  wherein the final recrystallization annealing is performed at about 1900° C.  
     
     
         14 . The method of  claim 11  wherein the molybdenum-lanthana alloy contains from about 0.4 weight percent to about 1.0 weight percent lanthana.  
     
     
         15 . The method of  claim 11  wherein the molybdenum-lanthana alloy contains from about 0.6 weight percent to about 0.7 weight percent lanthana.  
     
     
         16 . The method of  claim 13  wherein the degree of deformation is from about 12% to about 17%.  
     
     
         17 . The method of  claim 16  wherein the molybdenum-lanthana alloy contains from about 0.6 weight percent to about 0.7 weight percent lanthana.