Influence of the thermomechanical processing on the fracture mechanisms of high strength aluminium/pure aluminium multilayer laminate materials

摘要

The microstructure and mechanical properties, with emphasis in the impact\udfracture toughness behaviour, of two multilayer laminate materials have been\udinvestigated. The multilayer materials are constituted by alternated sheets of pure\udaluminium (Al 1200 or Al 1050) and high strength Al 7075 alloy. Stacked layers of\udthese alloys have been successfully joined using two processing routes with different\udtotal hot rolling strains. Both laminates have been tested at room temperature under\udimpact Charpy tests, 3-point bend tests and shear tests on the interfaces. Both laminates\udexhibited more than eight times improvement in impact fracture toughness over the\udmonolithic Al 7075-T6. The toughness increase in the higher rolling strained laminate is\udalmost entirely due to crack blunting mechanism, while in the lower strained laminate,\udcrack deflection by delamination and crack renucleation processes were active.