United States of America As Represented by the Secretary of the Air Force

David S Lee

Dennis M Dimiduk

Sheldon L Semiatin

A heat treatment method for producing moderate .alpha. grain size (50-250 .mu.m) fully lamellar, microstructures in thin cross section near-.gamma. titanium aluminide alloy products is described, wherein a wrought, fine y grain starting microstructure is heated at a temperature high in the two-phase .alpha.+.gamma. phase field and 30-60.degree. C. below the .alpha. transus temperature to produce a structure of small equiaxed .alpha. grains (about 25 .mu.m dim) and fine .gamma. phase grains, which is then briefly heated to a temperature in the single-phase .alpha. field in order to complete dissolution of remnant .gamma. grains and to minimize growth of .alpha. grains. The material is then cooled to transform the microstructure to fully lamellar .alpha..sub.2 +.gamma..

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Chesterfield, MO, United States of America

David S Lee