Abstract A process for making nickel-based superalloys that possess excellent high-temperature properties which includes the steps of providing a metal powder having a controlled amount of oxygen and carbon which is confined and densified at an elevated temperature forming a billet that can be further deformed, if desired, to provide an appropriate shaped component. Thereafter, the billet or deformed part is subjected to heat treatment to effect a growth in the grain size thereof to attain optimum physical properties, whereafter the alloy is carburized to increase the carbon content thereof to a level in excess of about 500 parts per million (ppm) which is performed in a manner so as to preferentially promote carbide formation at the grain boundaries of the alloy, thereby stabilizing the alloy against further grain growth when subjected to elevated temperatures during use.
The process as described in claim 1, including the further step of subjecting the carburized said alloy to a solution annealing treatment at an elevated temperature.
Claim 2
Dependent Claim
19 words
The process as described in claim 1, including the further step of microcasting the superalloy to provide said powder.
Claim 3
Dependent Claim
31 words
The process as Described in claim 1, wherein said powder is generally spherical in configuration and is of a particle size ranging from about 1 micron up to about 60 mesh.
Claim 4
Dependent Claim
37 words
The process as described in claim 1, wherein the carburizing step is carried out to the extent where the carbon content of said alloy is within a range of from about 500 ppm to about 2000 ppm.
Claim 5
Dependent Claim
25 words
The process as described in claim 1, including the further step of deforming said billet to a desired configuration prior to the heat treatment thereof.
Claim 6
Dependent Claim
25 words
The process as described in claim 1, in which said powder contains less than about 100 ppm oxygen and less than about 300 ppm carbon.
Claim 7
Dependent Claim
48 words
The process as described in claim 1, wherein said billet derived from said densifying step has a grain size of less than about 1 X 10 4 inch and including the further step of superplastically deforming said billet to a desired configuration prior to the heat treatment thereof.
Claim 8
Dependent Claim
50 words
The process as described in claim 1, wherein the densification of said powder into said billet is achieved by confining said powder in a sealed deformable container and compacting said powder while in said container which is preheated to a temperature ranging from about 1900* F. to about 2500* F.
Claim 9
Dependent Claim
38 words
The process as described in claim 1, in which the carburization of said billet is accomplished by a gas carburizing technique carried out at a temperature of less than about one-half the absolute melting point of said alloy.