Method of forming non-sag molybdenum-lanthana alloys
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.