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:
Dec. 15, 1998
Filed:
Dec. 16, 1996
Sami M El-Soudani, Cerritos, CA (US);
Boeing North American, Inc., Seal Beach, CA (US);
Abstract
The invention is a process for simultaneously improving at least two mechanical properties of mill-processed (.alpha.+.beta.) titanium alloy, which may or may not contain silicon, which includes steps of heat treating the mill-processed titanium alloy such that the (.alpha.+.beta.) microstructure of said alloy is transformed into an (.alpha.+.alpha..sub.2 +.beta.) microstructure, preferably containing no silicides. The heat treating steps involve subjecting the mill-processed titanium alloy to a sequence of thermomechanical process steps, and the mechanical properties which are simultaneously improved include (a) tensile strength at room, cryogenic, and elevated temperatures; (b) fracture toughness; (c) creep resistance; (d) elastic stiffness; (e) thermal stability; (f) hydrogen embrittlement resistance; (g) fatigue; and (h) cryogenic temperature embrittlement resistance. As a consequence of the process, the (.alpha.+.alpha..sub.2 +.beta.) microstructure contains equiaxed alpha phase strengthened with .alpha..sub.2 precipitates coexisting with lamellar alpha-beta phase, where the .alpha..sub.2 precipitates are confined totally to the equiaxed primary alpha phase. The invention also encompasses a composition of matter produced by the inventive process, especially one comprising a titanium alloy having an (.alpha.+.alpha..sub.2 +.beta.) microstructure.