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:
Sep. 04, 2001
Filed:
Jun. 30, 1998
Young-Won Kim, Dayton, OH (US);
Dennis M. Dimiduk, Beavercreek, OH (US);
The United States of America as represented by the Secretary of the Air Force, Washington, DC (US);
Abstract
Methods are presented to produce duplex (DP) microstructures, nearly lamellar (NL) microstructures, and fully TMT lamellar (TMTL) microstructures in gamma titanium aluminide alloy articles. The key step for obtaining a specific type of microstructure is the post-hot work annealing treatment at a temperature in a specific range for the desired microstructure. The annealing temperatures range from T +100° C. to T&agr;−25° C. for duplex (DP) microstructures, from T&agr;−25° C. to T&agr;−5° C. for nearly lamellar (NL) microstructures, and from T&agr; to T&agr;+60° C. for fully TMT lamellar (TMTL) microstructures, where T is the titanium-aluminum eutectoid temperature of the alloy and T&agr; is the alpha transus temperature of the alloy. The times required for producing specific microstructures range from 2 min to 15 hours depending on microstructural type, alloy composition, annealing temperature selected, material section size, and desired grain-size. The heating rate to the post-hot work annealing treatment is critical and must be fast enough to avoid compositional segregation (in the two-phase field) and uneven grain growth. Cooling schemes and rates after the annealing treatments are determined according to the microstructural features of interest, and their stability.