Abstract A microstructure-based numerical simulation is performed to understand the mechanical properties and fracture of a Ti-Al3Ti core-shell structured particulate reinforced A356 composite ((Ti-Al3Ti)cs/A356). A series of two-dimensional (2D) representative volume element (RVE) models are generated automatically by embedding Ti-Al3Ti core-shell structured particulates in an A356 matrix. Microstructure-based 2D RVE of monolithic Al3Ti particulate reinforced A356 composite (Al3Tip/A356) is also simulated for comparison. The ductile fracture of both Ti core and A356 matrix as well as the brittle fracture of the Al3Ti shell are considered. The simulation confirms that the high elongation of the (Ti-Al3Ti)cs/A356 composite is attributed to the uniform distribution of the overall ductile globular reinforcing particulates, which prevent a premature failure effectively by reducing local stress concentration both on and inside the core-shell structured particulates. The surrounding ductile phases of the Al3Ti shell blunt the crack tips effectively and, therefore, restricting the propagation of the cracks in a nominal strain range of 2.2%–6.1%. For both (Ti-Al3Ti)cs/A356 and Al3Tip/A356 composites, the simulation results are in good agreement with microstructural observations during an in-situ tensile test in a scanning electron microscope.

中文翻译：

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基于微观结构的 Ti-Al3Ti 核壳结构颗粒增强 A356 复合材料力学性能和断裂的数值模拟

摘要 进行了基于微观结构的数值模拟，以了解 Ti-Al3Ti 核壳结构颗粒增强 A356 复合材料 ((Ti-Al3Ti)cs/A356) 的力学性能和断裂。通过在 A356 基体中嵌入 Ti-Al3Ti 核壳结构颗粒，自动生成一系列二维 (2D) 代表性体积元 (RVE) 模型。还模拟了单片 Al3Ti 颗粒增强 A356 复合材料 (Al3Tip/A356) 的基于微观结构的 2D RVE 以进行比较。考虑了 Ti 核和 A356 基体的韧性断裂以及 Al3Ti 壳的脆性断裂。模拟证实 (Ti-Al3Ti)cs/A356 复合材料的高伸长率归因于整体延性球状增强颗粒的均匀分布，通过减少核壳结构颗粒上和内部的局部应力集中，有效地防止过早失效。Al3Ti 壳周围的延展相有效地钝化了裂纹尖端，因此将裂纹的扩展限制在 2.2%–6.1% 的标称应变范围内。对于 (Ti-Al3Ti)cs/A356 和 Al3Tip/A356 复合材料，模拟结果与扫描电子显微镜原位拉伸试验期间的微观结构观察结果非常吻合。