Experimental Finding Of Initiation Fracture Toughness And FEM Simulation Of Fracture Behaviour Of UFG 7075 Al Alloy

The present work describes an experimental evaluation of yield strength, tensile strength, initiation fracture toughness and Finite element simulations of fracture behaviour for both bulk and ultrafine-grained (UFG) 7075 Al Alloy. The 7075 Al alloy has been rolled for different thickness reductions (40%, 70% and 90%) at cryogenic (liquid nitrogen) temperature, and its mechanical properties and microstructural morphology have been investigated. Rolling of the Al alloy at cryogenic temperature suppresses the dynamic recovery and grain growth, which leads to grain fragmentation. Dislocation cells formed during consecutive rolling passes, transformed into fully formed UFG (600 nm) up to 70% thickness reduction. Grain size gets reduced further when 90% thickness reduction is achieved. Incremental crack growth simulations have been carried out by commercial software ABAQUS under quasi-static loading using deformation plasticity theory based on Griffith energy concept. J-integral, stress alon