The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 25, 1996
Filed:
Oct. 17, 1994
Duk Y Yoon, Seoul, KR;
Aldo E Murut, Schenectady, NY (US);
Michael F Henry, Schenectady, NY (US);
Renee M Rohling, Burnt Hills, NY (US);
Charles P Blankenship, Niskayuna, NY (US);
Mark G Benz, Burnt Hills, NY (US);
Edward L Raymond, Maineville, OH (US);
Eric S Huron, West Chester, OH (US);
General Electric Company, Cincinnati, OH (US);
Abstract
A method is provided for obtaining uniform grain growth within .gamma.' precipitation strengthened nickel-base superalloys. The method includes forming a billet having a very fine grain size in order to achieve optimum superplasticity of the superalloy during forging. The article is then heated to a pre-working hold temperature in a manner which prevents coarsening of the microstructure and a loss of superplasticity. The article is then worked, such as by forging, at a temperature below the .gamma.' solvus temperature of the alloy, so as to maintain local strain rates within the article below a critical strain rate for random grain growth, and so as to maintain the strain rate gradient throughout the article below a critical upper limit. After working, the article is subjected to annealing at a temperature which is less than the .gamma.' solvus temperature of the alloy, and for a duration which is sufficient to remove accumulated metallurgical strain in the article. A supersolvus heat treatment is then performed by further heating the article to a temperature above the .GAMMA.' solvus temperature of the superalloy for a duration sufficient to uniformly coarsen the grains of the article.