Room-temperature low-cycle fatigue and fracture behaviour of asymmetrically rolled high-strength 7050 aluminium alloy plates

The asymmetrical rolling (ASR) process with shear deformation is considered as a promising technology to adjust/improve through-thickness microstructure homogeneity and integrated properties of high-strength aluminium alloy plates. But the advantages may come caveats that are subject our research. In this paper, room-temperature low cycle fatigue fracture behaviour ASR-ed AA7050 plates compared symmetrical (SR) one. It shown after either type exhibit similar low-cycle lives but SR-ed one displays better cyclic ability slightly higher at high strain amplitudes. demonstrated severe surface-localized contributes formation slip relief on surface subsequently initiates micro-cracks propagated via transgranular and/or intergranular modes along obvious striations. Recrystallised grains coarse grain boundary precipitates wide precipitate-free zones near upper/bottom layers well numerous larger secondary particles in cause early crack initiation for short life. However, plate more frequent subgrains layers, fine less indissoluble could possess initiation/propagation resistance loading behaviour. Fine microhardness/strength can facilitate passing dislocations or bands into adjacent so delay propagation such energy-intensified extending Properly balancing strain/deformation distribution recrystallization/indissoluble implementing feasible ASR becomes critical issue achieve fracture-resistant microstructures underlying causes/mechanisms regarding differences mechanical revealed discussed based modelling temperature/strain detailed characterization.