METHOD FOR PREPARING ULTRA-FINE GRAIN TITANIUM AND TITANIUM-ALLOY ARTICLES AND ARTICLES PREPARED THEREBY

摘要

A method for preparing ultra-fine grain titanium or titanium-alloy articles 78 used for adjoining or assembling of detail components. Coarse- grained titanium or titanium-alloy materials 52 typically are heated and forced unde r constant pressure through a friction stir processing tooling device 50 containing a stirring chamber 54 and a stirring rod 58. As the material is passed through the stirring chamber 54, the stirring rod 58 solutionizes the titanium or titanium-alloy material 52 and stirs the material to obtain a homogeneous or uniform material condition . As the processed material exits the stirring chamber 54 of the friction stir proces s tooling device 50, it reconsolidates as an extremely homogeneous structure possessin g ultra- fine grain structure. Titanium or titanium-alloy materials 52 having been processed to achieve such ultra-fine grain material structure may then be manufactured in to aerospace structural articles or components such as fasteners 78 or articles that do not require a subsequent thermal or heat-treatment steps. The resulting fastener s; articles or components have improved material performance characteristics associated with this ultra-fine grain material structure.