Layered Ti-Al metal composite (LMC) was designed and fabricated by hot-rolling and annealing of pure Ti and Al sheets. The as-prepared composite exhibits high tensile ductility, being superior to any individual Ti or Al sheets. The stress/strain evolution and fracture behavior of the LMC were analyzed by in-situ observations during the tensile deformation. Three deformation stages of LMC were clearly observed by neutron diffraction: elastic stage, elastic-plastic stage and plastic stage. It is found that stress partitioning at the elastic-plastic deformation stage improves the strain balance of LMC, but leads to an internal stress accumulated at the interface. Additionally, a strain-transfer from Ti to adjacent Al layers relieves the strain localization of Ti layers in LMC, which improves the ductility of Ti. Both stress partitioning and strain localization of Ti layers facilitate the nucleation of cracks at a low macro strain. However, the crack propagation is constrained by layered structure. In terms of the Al layers, the constrained micro-cracks relieve the stress concentration in Al layer and improve the ductility of Al layers, so that cracking indirectly affects the plastic deformation behavior of LMC, then improving its entire ductility. This work provides a new structural strategy towards simultaneously improving strength and ductility to develop high performance LMC by structural design.

通过对纯Ti和Al板进行热轧和退火来设计和制造层状Ti-Al金属复合材料（LMC）。所制备的复合材料表现出高拉伸延展性，优于任何单独的Ti或Al板。在拉伸变形过程中通过现场观察分析了LMC的应力/应变演变和断裂行为。通过中子衍射可以清楚地观察到LMC的三个变形阶段：弹性阶段，弹塑性阶段和塑性阶段。发现在弹塑性变形阶段的应力分配改善了LMC的应变平衡，但是导致在界面处累积的内部应力。另外，从Ti到相邻的Al层的应变转移减轻了LMC中Ti层的应变局部化，从而提高了Ti的延展性。Ti层的应力分配和应变局部化都有助于在低宏观应变下使裂纹成核。但是，裂纹扩展受到分层结构的限制。在铝层方面，受约束的微裂纹减轻了铝层中的应力集中并提高了铝层的延展性，因此开裂间接影响了LMC的塑性变形行为，从而改善了其整体延展性。这项工作为通过结构设计同时提高强度和延展性来开发高性能LMC提供了一种新的结构策略。受约束的微裂纹缓解了Al层中的应力集中，提高了Al层的延展性，因此裂纹间接影响了LMC的塑性变形行为，从而提高了LMC的整体延展性。这项工作为通过结构设计同时提高强度和延展性来开发高性能LMC提供了一种新的结构策略。受约束的微裂纹缓解了Al层中的应力集中，提高了Al层的延展性，因此裂纹间接影响了LMC的塑性变形行为，从而提高了LMC的整体延展性。这项工作为通过结构设计同时提高强度和延展性来开发高性能LMC提供了一种新的结构策略。