Formation mechanism and elimination method for surface groove of the hollow lattice structure by superplastic forming

Abstract. The titanium alloy hollow lattice structures can be widely applied on the advanced aircrafts due to their excellent mechanical properties and light weight. Superplastic forming diffusion bonding (SPF/DB) process is an manufacture these with two outer plates one inner plate. To further decrease weight of structures, thinner plate preferred when compared plate, however, it would result in occurrence surface groove at intersects between stiffener during superplastic process, leading failure structures. In this paper, formation characteristics influence outer/inner sheet thicknesses grooves was investigated through a well-developed finite element model. Furthermore, innovative method presented eliminate SPF/DB, which makes use double-sided dynamically adjusted gas pressure process. Based developed numerical models, effects assistant parameters have been investigated. effectiveness proposed new optimized validated by performing SPF/DB tests typical study provides way improve quality accuracy parts SPF/DB.