Impact toughness improvement of high strength aluminium alloy by intrinsic and extrinsic fracture mechanisms via hot roll bonding

A multilayer aluminium laminate comprising ten layers of Al-Zn-Mg-Cu alloy (82 vol.%) and nine layers of pure aluminium (18 vol.%) has been processed by hot rolling. The rolled laminate was characterized by electron backscattering diffraction, Charpy impact and shear tests. The multilayer laminate showed an outstanding Charpy impact toughness, being eighteen times higher than that for the as-received Al-Zn-Mg-Cu alloy. Damage tolerance improvement was due to the high volume fraction of the high strength aluminium and extrinsic fracture mechanisms.Financial support from CICYT (Project MAT2003-01172 and MAT2006-11202) is gratefully acknowledged. C.M. Cepeda-Jiménez thanks the CSIC for a I3P contract. We also thank F.F. González-Rodríguez for assistance during hot rolling and J. Chao- Hermida for assistance with the Charpy impact test.Peer reviewe