This study presents a novel approach for fabricating SiC-reinforced magnesium matrix composites by combining digital light processing (DLP) with pressureless infiltration. Pre-oxidation of SiC powder enhanced its wettability with the magnesium alloy, enabling the near-net-shape fabrication of honeycomb Mg-based composites with precisely controlled SiC and Al 2 O 3 powder ratios. The influence of varying ceramic content on the microstructure and compressive properties of the composites was investigated, revealing significant mechanical anisotropy. A combined approach utilizing fracture morphology analysis and finite element simulations elucidated the compressive behavior and failure mechanisms of the composites under different loading directions. This work not only offers a promising route for on-demand design and fabrication of Mg-based composites but also provides valuable insights into understanding the mechanical behavior of architected composites.
In this work, poly- p -phenylene benzobisoxazole (PBO) fibers reinforced polybenzimidazole (PBI) resin-based laser ablation composites (thickness = 5 mm) with different SiC contents were prepared. SiC/PBI/PBO composites exhibited good mechanical properties , excellent thermal stability and laser ablation properties. The laser ablation properties and ablation mechanism of the composites were investigated using a high-energy continuous-wave laser (30 MW·m −2 ). Increasing the SiC content led to increase in composites density, while decreasing the bending performance of the composites. However, it improves the mass and linear ablation rates, resulting in an overall improvement in ablation properties. At a SiC content of 70 %, the composite exhibited a mass loss of 8.2 %, a mass ablation rate of 9.2 mg·s −1 , and a linear ablation rate of 0.11 mm·s −1 . The ablation process of SiC/PBI/PBO composites was delineated into pre-ablation and post-ablation stages, with the ablated composites divided into the ablation center, transition region, and outer region based on morphological characteristics. After ablation, numerous white hollow SiO 2 spheres and SiO 2 protective layers were formed in the ablation centers, the transition regions were deformed and cracked, while the outer region remained unscathed.
Qinghua Feng,Panpan Lin,Tiesong Lin,Peng He,Yan Liu,Weimin Long,Jian Li
A novel design of a multi-layered joint architecture, characterized by the controllable spatial distribution of ceramic reinforcements, was obtained, when brazing ZrB 2 -SiC ceramics and Ti-6Al-4 V reinforced by TiB whiskers with AgCu filler. To induce SiC reinforcements to cluster together, within the center of the filler and especially away from the ZrB 2 -SiC, SiC was added into joint, in the form of a SiC interlayer featuring a 3D-bridged network structure with continuous micro-channels infiltrated by capillary force by liquid filler during brazing. Different SiC particles were connected together, by micro-bridges being not destroyed during brazing. The layer rich in SiC could reduce thermal expansion mismatch between different substrates, the AgCu next to the ZrB 2 -SiC could relax the strain energy by high plastic deformation. Compared to joint brazed with single AgCu, joint strain energy decreased from 10.8 × 10 −6 J to 8.6 × 10 −6 J, accordingly joint shear strength increased from ∼5.4 MPa to ∼41.2 MPa.
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