Abstract
Al 6351 is extensively utilised in aerospace and automotive applications due to its excellent mechanical properties. These properties can be further enhanced through a combination of work hardening via cryorolling (CR) and precipitation hardening via post-annealing (PA) treatment, making the resulting Al 6351 alloy more suitable for various structural applications in these industries. For CR treatment, the solution-treated (ST) sample of Al 6351 alloy was exposed to a true strain of 2.3, and the PA was carried out for CR Al 6351 alloy at 100 to 350 °C temperature range for 1 hour. Despite the potential of CR and PA to improve mechanical properties, their effectiveness has not been reported so far. The mechanical behaviour of the different processing conditions was investigated using tensile and fracture toughness tests. The CR sample annealed at 100 °C showed a peak hardness of (90 HV), tensile (UTS of 306 MPa), and fracture toughness parameters (K_Q = 11.2 MPa √m, K_ee = 20.9 MPa √m, and J integral = 13.8 kJ m⁻²). The fracture toughness of cryorolled + annealed samples remain consistent until the annealing temperature of 200 °C but shows a sharp decline beyond 200 °C.

Key words
severe plastic deformation, aluminium alloy, fracture toughness, structure property correlation

Full text (4188 KB)