Sadeghi Behzad, Cavaliere Pasquale, Sanayei Mohsen
Department of Innovation Engineering, University of Salento, Lecce, Italy.
Metallurgist and Materials Engineering Technical Lead, Department of Innovation and Sustainability - Product Development, Husky Technologies, Bolton, Ontario, Canada.
J Microsc. 2025 Jan;297(1):18-34. doi: 10.1111/jmi.13350. Epub 2024 Aug 6.
In this study, the effects of different sizes of reinforcing particles on the corrosion behaviour and mechanical properties of aluminium (Al)-based composites produced by spark plasma sintering (SPS) are analysed. In the study, the effects of SPS parameters, including electrical power, applied pressure and sintering temperature, on the consolidation process and microstructure evolution of the composite are closely investigated. The results reveal a nuanced relationship between the sintering conditions and the properties of the particles, which in turn determine the sintering dynamics and the formation of the microstructural features. The evaluation of mechanical properties indicates a remarkable influence of particle size distribution on the hardness of the composites, showing an initial improvement with the introduction of nanoparticles, followed by a slight decrease as the balance between nano- and micron-sized AlO particles shifts. A scanning electron microscopy (SEM) study demonstrates the influence of particle dimensions on the change of grain boundaries and the spatial arrangement of the composite matrix. Electrochemical experiments in a 0.1 M NaCl solution show a consistent corrosion potential (E) across all samples, while the current densities associated with corrosion (i) show considerable variation. The presence of nano-sized AlO particles was found to increase corrosion resistance, in contrast to the detrimental effects observed with larger microparticles. In particular, composites with a bimodal distribution of particle sizes showed a 3.5-fold increase in corrosion resistance compared to pure Al. The specific Al-2n8mAlO composite that exhibited active electrochemical properties at elevated potentials without a defined passivation range emphasises the significant role of particle size. This study draws attention to bimodal microstructures as a promising route to achieving uniformity and improved corrosion resistance in Al matrix composites, while pointing to the need for further research to fully elucidate the operative mechanisms.
在本研究中，分析了不同尺寸增强颗粒对通过放电等离子烧结（SPS）制备的铝基复合材料的腐蚀行为和力学性能的影响。在该研究中，密切研究了SPS参数（包括电功率、施加压力和烧结温度）对复合材料固结过程和微观结构演变的影响。结果揭示了烧结条件与颗粒性能之间的细微关系，这反过来又决定了烧结动力学和微观结构特征的形成。力学性能评估表明，颗粒尺寸分布对复合材料硬度有显著影响，随着纳米颗粒的引入，硬度最初有所提高，随后随着纳米和微米尺寸的AlO颗粒之间平衡的变化而略有下降。扫描电子显微镜（SEM）研究表明了颗粒尺寸对复合材料晶界变化和基体空间排列的影响。在0.1M NaCl溶液中的电化学实验表明，所有样品的腐蚀电位（E）一致，而与腐蚀相关的电流密度（i）显示出相当大的变化。与较大的微粒所观察到的有害影响相反，发现纳米尺寸的AlO颗粒的存在提高了耐腐蚀性。特别是，具有双峰粒径分布的复合材料的耐腐蚀性比纯铝提高了3.5倍。在较高电位下表现出活性电化学性能且无明确钝化范围的特定Al-2n8mAlO复合材料强调了粒径的重要作用。本研究提请注意双峰微观结构是实现铝基复合材料均匀性和提高耐腐蚀性的一条有前途的途径，同时指出需要进一步研究以充分阐明作用机制。
