Maolin Tian, Haokai Dong, Zixiang Liu, Zhenqiang Wang, Rui Zhong, Yangwei Wang, Keke Chang
Post-fabrication annealing is necessary for most metallic layered composites for stress-relief, while traditional isothermal annealing is inefficient and often leads to undesired intermetallic compounds. Here we explore the potentials of flash heating in tuning the microstructure and mechanical behavior of the as-rolled Ti6Al4V/Al sheets. It was interestingly found that flash annealing creates a bimodal heterogeneous microstructure in Al layer while preserving the deformed state in Ti6Al4V layer. The bimodal is characterized by the fine-grained zone near the interface and coarse grown grains in the interior. No intermetallic compounds were observed at the Ti6Al4V/Al interface. As compared to the as-rolled and slow-heating scenarios, such a unique microstructure leads to a substantial enhancement in ductility with marginal loss in strength. The formation mechanism underlying the bimodal Al grains was experimentally clarified, and the roles of fine-grained zone in local stress/strain partitioning were discussed using the crystal plasticity finite element method (CPFEM). This study demonstrates the applicability of flash annealing to produce high-performance layered composites, which may hold interests for both scientific and industrial communities.