In the quest to bolster the durability of materials used in harsh environments, a team of researchers led by Reza Jafari from Tampere University in Finland has made a significant stride. Their work, published in the journal *Applied Surface Science Advances* (translated to English as *Advances in Applied Surface Science*), focuses on enhancing the structural integrity of aluminum alloy coatings through the addition of quasicrystal particles. The findings could have substantial implications for the energy sector, where materials often face relentless wear and tear.
The study zeroes in on metal matrix composite (MMC) coatings, which combine the beneficial properties of different phases to offer functionalities beyond those of single-phase alloys. By reinforcing AA6061 aluminum alloy with hard Al-based quasicrystal particles, the researchers aimed to improve the final composite’s integrity. The coatings were deposited using high-pressure cold spray, a solid-state process that allows for the deposition of coatings without melting the feedstock materials. This method ensures that the reinforcement effect could be isolated and studied effectively.
“Quasicrystal particles, when dispersed as reinforcements in the final composite coating, reduce porosity and drive microstructural refinement,” explains Jafari. This refinement includes the formation of elongated and refined grains, which contribute to localized strengthening within the matrix. The nano-hardness of the matrix increased by over 50%, from 2.21 to 3.43 GPa, as revealed by dense in-situ nanoindentation and corresponding mapping of hardness and elastic modulus.
To assess the coating’s integrity, the researchers repurposed cavitation erosion testing. This method involves subjecting the coatings to intense pressure fluctuations, simulating the harsh conditions often encountered in industrial applications. The results were promising: the average cumulative volume loss was significantly reduced relative to AA6061 at 30 minutes of exposure. For the composites with 50 and 90 vol.% quasicrystal particles in the starting feedstock, the volume loss dropped to approximately 20% and 5%, respectively, compared to the non-reinforced coating.
Microstructural investigation of the eroded surfaces revealed a transition in the damage mechanism. In the non-reinforced coating, damage occurred through the detachment of particle chunks along AA particle boundaries. In contrast, the composite structures exhibited a more gradual and uniform removal of matrix and reinforcement as fine debris. This suggests improved coating durability, enhanced interparticle cohesion, and matrix strengthening.
The implications of this research are far-reaching, particularly for the energy sector. In environments where materials are subjected to extreme conditions, such as in turbines, pipelines, and offshore structures, the enhanced durability of these composite coatings could lead to longer service life and reduced maintenance costs. “Our findings suggest that these composite coatings could be a game-changer in industries where material integrity is paramount,” says Jafari.
As the energy sector continues to evolve, the demand for robust and durable materials will only grow. This research not only advances our understanding of metal matrix composites but also paves the way for innovative solutions that can withstand the rigors of industrial applications. With further development, these composite coatings could become a standard in the energy sector, ensuring safer and more efficient operations.
In summary, the work by Jafari and his team represents a significant step forward in the field of materials science. By enhancing the structural integrity of aluminum alloy coatings, they have opened up new possibilities for applications in the energy sector and beyond. The findings, published in *Applied Surface Science Advances*, highlight the potential of quasicrystal-reinforced composite coatings to revolutionize the way we approach material durability in challenging environments.