Failure Behavior of Layered Aluminum Matrix Composites Fabricated by SLM-Assisted Pressure Infiltration

Abstract:

Inspired by the nacreous structure of shells, layered HEA_P/Al-Al composites with varying framework thicknesses (0.3, 0.4, and 0.5 mm) were fabricated using selective laser melting (SLM) combined with pressure infiltration. The results indicate that the layered composites exhibit an intact internal structure, and a well-bonded interface between the reinforcement phase (HEA_P/Al) and the aluminum matrix, without the formation of interfacial reaction products. With increasing framework thickness, the flexural strength of the composites significantly improves, while the compressive strength decreases first and then increases. Additionally, the compressibility is notably enhanced. Among them, the composite with a 0.5 mm framework shows the best overall performance, with a flexural strength of 228 MPa, a compressive strength of 385 MPa, and a compressibility of 20.8%. Three-point bending tests reveal that the layered HEA_P/Al-Al composites exhibit a mixed ductile-brittle fracture mode, primarily characterized by the debonding of high-entropy alloy particles and tearing of the aluminum matrix, with the main crack propagating perpendicular to the aluminum framework. An increase in framework thickness leads to longer crack deflection paths, while mechanisms such as multi-crack propagation and microcrack diffusion effectively suppress the propagation of the main crack, thereby enhancing the overall strength and toughness of the composite. Finite element simulation results are consistent with experimental observations, confirming the inhibitory effect of the framework structure on main crack propagation. This study provides theoretical support for the structural design and mechanical performance optimization of heterogeneous composite materials.