Microstructure-based numerical simulation of the mechanical properties and fracture of a Ti-Al3Ti core-shell structured particulate reinforced A356 composite

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. [Display omitted] •Tensile and fracture of a Ti-Al3Ti core-shell structured particulate reinforced A356 composite were studied•Constitutive behaviors of the CS particulates are obtained by a reverse analysis algorithm from nano-indentation results•The high ductility of the Ti-Al3Ti CS particulate reinforced A356 composite is is well explained by simulation•The predicted fracture behavior shows a satisfactory agreement with the observation in in-situ tensile test