In-situ investigation of deformation behavior and fracture forms of Ti/Al/Mg/Al/Ti laminates
(1. College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Shanxi Key Laboratory of Advanced Magnesium-based Materials, Taiyuan University of Technology, Taiyuan 030024, China;
3. Instrumental Analysis Center, Taiyuan University of Technology, Taiyuan 030024, China;
4. Shanxi Institute of Energy, Taiyuan 030006, China;
5. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China)
2. Shanxi Key Laboratory of Advanced Magnesium-based Materials, Taiyuan University of Technology, Taiyuan 030024, China;
3. Instrumental Analysis Center, Taiyuan University of Technology, Taiyuan 030024, China;
4. Shanxi Institute of Energy, Taiyuan 030006, China;
5. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China)
Abstract: In-situ bending and stretching were conducted on hot-rolled and annealed Ti/Al/Mg/Al/Ti laminates, with a focus on crack initiation and propagation of intermetallics and component layers, which helps to clarify their deformation behavior and fracture forms. The results show that delamination is the early fracture form of laminate with or without intermetallics at Al/Mg interface, so Al/Mg interfacial bonding strength determines the mechanical properties of laminate. Various and irregular intermetallics cracks lead to Al/Mg interface delamination in annealed laminate and help to release stress. Necking and fracture of component layers are observed at the late deformation stage, and the sequence is Al, Mg and Ti layers, resulting from their strength. Angle between crack propagation direction and stretching direction of Mg layer both in rolled and annealed laminates is around 45° due to the effect of shear deformation, and crack convergence leads to final complete fracture of Mg layer.
Key words: Ti/Al/Mg/Al/Ti laminate; in-situ test; intermetallics; crack initiation; fracture form