SUPERPLASTIC FORMING TECHNOLOGY OF AIRCRAFT STRUCTURES FOR AL-LI ALLOY AND HIGH-STRENGTH AL-ALLOY

Superplastic 2091 and 7475 sheets have been used to fabricate load-bea ring aircraft structures, the results showing that a mass reduction of approximately 15% and a cost saving of 25% are obtained for the forme d structures. This paper presents the manufacturing techniques of 2091 and 7475 parts, which have complex shape and a maximum true thickness strain of 0.92. The cavitation, post-SPF mechanical characteristics, SPF parameters, thickness distribution, heat treatment and surface tre atment are discussed also. (C) 1997 Elsevier Science S.A.