Extraordinary room temperature tensile ductility of laminated Ti/Al composite: Roles of anisotropy and strain rate sensitivity

Abstract

Al/Ti/Al laminated metal composites (LMCs), with layer thicknesses ≥800 μm, were fabricated via hot rolling bonding and annealing. The fabricated Al/Ti/Al LMCs displayed improved tensile ductility compared with both the single Ti and single Al layers. Combinational analyses based on digital image correlation and finite element modeling revealed that the width of the interface affected zones (IAZ) could exceed 150 μm, which is more than one order of magnitude larger than previously reported values. The mismatch of plastic anisotropy between the Ti layer and the Al layer may play a crucial role in realizing such a wide IAZ. Slip trace analysis indicated that more pyramidal and basal slips were activated at the Ti/Al interface than in the central part of the Ti layer, which may be attributed to the complex stress/strain state in the IAZ. Although a wide IAZ was observed, the strain hardening capability of the Al/Ti/Al LMCs did not obviously improve. In contrast, the strain rate sensitivity improved, which is assumed to play a key role in the improved ductility of the Al/Ti/Al LMCs. This study can provide a direction for the design of heterostructured materials with high strength and high ductility.