Combined effect of heat treatment and rolling on pre-strained and SPDed aluminum sheet

Abstract

Specimens of pre-strained and severely deformed aluminum alloy AA1350 are undergone rolling and heat treatment at 125, 200 and 275°C on their final processing history. The combined effect of rolling and post-annealing on the mechanical properties and microstructural evolutions is investigated. The main effort is focused on the ductility of specimens tolerating duplex straining paths. Results show that adequate annealing can effectively enhance ductility without noticeable decrease in the strength of the specimens at 200°C and before recrystallization starts. During microstructural evolutions, no rapid grain/crystallite growth is observed at lower temperatures; however, treatment at 275°C considerably changes mechanical characteristics by equiaxing the lamellar structure. According to the examinations, it is concluded that pre-straining through constrained groove pressing with the strain of 1.16 and subsequently imposing rolling strain up to the strain of 1.23 results in aluminum having extremely limited ductility and ultra-fine microstructure free of micro-cracks. By annealing at 200°C, the considerable recovery of elongation (up to 4.6%) is achieved and this is noticeable compared to the ductility of non-heat treated and severely deformed aluminum (approximately 1%).