Design and fabrication of bionic Bouligand-structured SiC/2024Al composites via binder jetting additive manufacturing and pressure infiltration

Abstract

Metal matrix composites (MMCs) are widely used in high-end manufacturing. However, the tradeoff between the strength and toughness of these materials poses a problem. In this study, inspired by nature, bionic Bouligand-structured SiC/2024Al composites with a pitch angle in the range of 15°–45° were designed using SolidWorks software and prepared via binder jetting additive manufacturing and pressure infiltration. Their SiC content was about 11.6 vol%, and their porosity ranged from 1.59 % to 2.80 %. A periodic structure was confirmed from microstructural observations and a micro-computed tomography examination. Furthermore, a pitch-angle-related mechanical property was observed in the composites. In particular, finite element analysis showed that the 45°-pitch-angle composite had lower stress concentration and higher load carrying capacity than the composites with other pitch angles. After solution and aging treatment, nano-scale θ′ and S′ phases precipitated in the matrix, resulting in Orowan strengthening behavior. Consequently, the heat-treated 45°-pitch-angle composite showed a higher compressive strength of 741.59 MPa, a compressive strain exceeding 30 % and a K_IC value of 13.32 MPa m^1/2. The results of this study are expected to contribute to development of methods to overcome the strength-toughness tradeoff problem in MMCs.