To overcome strength-ductility trade-off in particulate metal matrix composites (PRMMCs), we developed a novel and controllable strategy, for the first time, via a combination of micro/nano-reinforcements and ultrafine/coarse-grained (UFG/CG) matrices. A powder assembly was developed to fabricate micro B₄C_p/6061Al composites, which features UFG/CG matrices containing ex/in-situ nano dispersoids and exhibits superior combination of strength and ductility. It was found that such a novel architecture possesses both intrinsic and extrinsic toughening. As the intrinsic toughening mechanisms, enhanced dislocation storage capability of UFG regions, twinning, and hetero-deformation induced toughening were detected. Moreover, crack-deflection induced by nano dispersoids as well as crack-blunting at UFG/CG regions were considered as the main extrinsic toughening mechanisms. The proposed strategy can be applied to design the architecture of other PRMMCs with both high strength and high ductility. Aluminum alloys; Powder processing; Heterostructures; Particulate reinforced composites; Microstructural toughening

为了克服颗粒金属基复合材料 (PRMMCs) 中的强度-延展性权衡，我们首次通过结合微/纳米增强材料和超细/粗晶粒 (UFG/CG) 开发了一种新颖且可控的策略矩阵。开发了一种粉末组件来制造微型 B ₄ C _p /6061Al 复合材料，该复合材料具有 UFG/CG 基质，含有非原位纳米分散体，并表现出优异的强度和延展性组合。发现这种新颖的结构同时具有内在和外在的增韧。作为内在增韧机制、增强的UFG区域的位错存储能力、孪晶和异质变形诱导的增韧进行了检测。此外，纳米弥散体引起的裂纹偏转以及UFG/CG区域的裂纹钝化被认为是主要的外在增韧机制。所提出的策略可应用于设计具有高强度和高延展性的其他 PRMMC 的结构。铝合金；粉体加工；异质结构；颗粒增强复合材料；微结构增韧