Author:R. T. Li, Z. Y. Wang, W. Sun, H. L. Hu, K. A. Khor, Y. Wang, Z. L. Dong

Institute: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore

Microstructure and strengthening mechanisms in Al/Al–Cu–Cr–Fe composites obtained by spark plasma sintering are a complex and multifaceted object of study that requires a deep understanding of the physical and metallurgical processes. Spark plasma sintering, as a method, allows for the effective combination of various components by forming plasma discharges, which contributes to better particle fusion and a decrease in the porosity of the final product.

This paper focuses on the nature of the microstructure, identifying the role of various additives such as copper, chromium and iron in the hardening process. The studies show that the addition of alloying elements significantly affects the distribution of phase components, which in turn increases the mechanical properties of the composite such as compressive strength and hardness.

In this study, Al-Cu–Cr–Fe quasicrystal reinforced aluminum-based composites were prepared using spark plasma sintering (SPS) method. The microstructural changes and compaction mechanisms as well as strengthening methods of these composites were analyzed. Due to their low thermal and electrical conductivity, the temperature of Al-Cu–Cr–Fe particles remained very low during sintering, which contributed to the preservation of their icosahedral phase and rough surface, ensuring adhesion to the aluminum matrix. The addition of Al–Cu–Cr–Fe increased the strength of the composite from 91.2 ± 2.8 MPa to 298.7 ± 6.4 MPa. Plastic deformations around the solid Al-Cu–Cr-Fe particles contributed to the compaction of the composite, creating a high dislocation density at the interface, which significantly contributed to the increased strength of the materials.

Reducing the weight of structures to improve fuel efficiency remains a priority in industries such as aviation, automotive, and space. Existing materials need to be replaced with better ones, and in this context, aluminum-based metal matrix composites are a promising alternative due to their low density and high strength. Composites using various reinforcing materials such as ceramics, metallic glasses, and carbon nanotubes have also demonstrated their effectiveness. Quasicrystals, which have high strength and wear resistance, are promising reinforcing components for such composites.

Strengthening mechanisms, such as the involvement of dislocation structures and the formation of interphase interactions, are key to determining the performance characteristics of the material. In conclusion, the results of this analysis open up broad prospects for further research in the field of improving the technologies for producing high-strength metal composites.