Heterogeneous metals and alloys are a new class of materials with superior mechanical properties.In this paper,we engineered sandwich-structured pure aluminum laminates composed of middle coarse-grained layer and oute...Heterogeneous metals and alloys are a new class of materials with superior mechanical properties.In this paper,we engineered sandwich-structured pure aluminum laminates composed of middle coarse-grained layer and outer fine-grained layer via extrusion,rolling and annealing.By controlling the post-annealing regimes,a larger degree of microstructure heterogeneities such as boundary spacing,misorientation and texture across the hetero-interface were obtained,which resulted in obvious mechanical differences.Tensile tests indicated that the 300℃/30 min annealed laminates enabled a relatively high tensile ductility while simultaneously retaining a high strength,which was better than prediction by the rule-of-mixture.To explain the reasons behind it,the evolution of geometrically necessary dislocations and strain gradient at the hetero-interface zone were detected using in-situ tension and microscopic digital image correlation technique.It was found that with the increasing applied strain,a significant strain gradient was developed near the interface,which was accommodated by geometrically necessary dislocations,thereby contributing to higher hetero-deformation induced(HDI)strengthening and hardening.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52071035 and U1764253)。
文摘Heterogeneous metals and alloys are a new class of materials with superior mechanical properties.In this paper,we engineered sandwich-structured pure aluminum laminates composed of middle coarse-grained layer and outer fine-grained layer via extrusion,rolling and annealing.By controlling the post-annealing regimes,a larger degree of microstructure heterogeneities such as boundary spacing,misorientation and texture across the hetero-interface were obtained,which resulted in obvious mechanical differences.Tensile tests indicated that the 300℃/30 min annealed laminates enabled a relatively high tensile ductility while simultaneously retaining a high strength,which was better than prediction by the rule-of-mixture.To explain the reasons behind it,the evolution of geometrically necessary dislocations and strain gradient at the hetero-interface zone were detected using in-situ tension and microscopic digital image correlation technique.It was found that with the increasing applied strain,a significant strain gradient was developed near the interface,which was accommodated by geometrically necessary dislocations,thereby contributing to higher hetero-deformation induced(HDI)strengthening and hardening.
