Springback control of Ti2AlNb alloy ultra-thin corrugated sheets via current-targeted loading during current-assisted roll forming process

Abstract

This paper proposes a novel current-assisted roll forming process for Ti₂AlNb alloy ultra-thin corrugated sheets, which enables local targeted loading of pulsed current, leveraging the electromigration effect to eliminate springback defects. First, the effect of pulsed current on the springback of Ti₂AlNb alloy foils during V-shaped bending was analyzed. The springback angle of the foils significantly decreases as the current density increases, particularly when it exceeds 20 A/mm². With a current density of 80 A/mm², the springback angle is only 0.3°. Subsequently, the deformation mechanism of Ti₂AlNb alloy ultra-thin corrugated sheets during the current-assisted roll forming process was elucidated. The strain field and current density field exhibit significant non-uniform distribution and dynamic evolution, with strain and current density concentrated at local bending corners. The springback angles of the corrugated sheet range from 0.2° to 0.6° under a loading current of 125 A. A prediction model for the forming angle of Ti₂AlNb alloy ultra-thin corrugated sheets was established based on a classical stress relaxation equation modified to include the effect of pulsed current and an approximate substitution of the current density history. The model achieved a relative average absolute error of 8.1%. The effective springback control of the Ti₂AlNb alloy ultra-thin corrugated sheet may be attributed to the electromigration effect of the pulsed current, since the Joule heating effect was suppressed.