Microstructure Evolution and Mechanical Behaviors of SiCp/CNTs Hybrid Reinforced Al-Si-Cu-Mg Composite by Semi-solid Stir Casting

作者：Zhenlin Zhang, Ying Xiao, Jun Xu, Chao Li, Fengliang Tan, Yajun Luo, Kecai Liu · 发表于：Materials Research · 年份：2024 · DOI：10.1590/1980-5373-mr-2023-0572 · 被引用次数：4 · 研究领域：Aluminum Alloys Composites Properties、Aluminum Alloy Microstructure Properties、Advanced Welding Techniques Analysis

In this study, Al-Si-Cu-Mg composites reinforced with Silicon carbide (SiC) particles and/or Carbon nanotubes (CNTs) were fabricated using semi-solid stirring casting technology (SSC). The aim of the study was to investigate the influence of SiC and/or CNTs on the mechanical properties, microstructural evolution, and deformation mechanisms of the Al-Si-Cu-Mg alloy. The findings indicated that the presence of SiC/CNTs in the composite had a significant effect on refining the α-Al phase and altering its grain orientation. Additionally, the results obtained from EBSD and TEM revealed that the microstructure of the Al-Si-Cu-Mg-SiC/CNTs hybrid composite (HAMC) underwent dynamic recrystallization (DRX) and static recrystallization (SRX), resulting in a fine equiaxed recrystallized structure. This process also led to the formation of high-angle grain boundaries (HAGBs) through dislocation rearrangement. The SiC particles were evenly distributed within the matrix, ensuring good interface bonding between SiC and α-Al phases. Moreover, the CNTs reacted with the matrix, resulting in the in-situ formation of the Al4C3 phase at the interface. The addition of SiC/CNTs significantly increased the tensile strength of HAMC at 25°C and 250°C, from 319MPa and 178MPa to 438MPa and 331MPa. Examination of the fracture surface of the hybrid composite unveiled that void formation occurred primarily at the regions surrounding the matrix-particle interface.