To reduce the cost of nanocomposites and improve the dispersion of nanoparticles, Al₂O_3np/SiC_np/Al hybrid nanocomposites are fabricated by combining liquid-state blowing and ultrasonic-assisted casting. The average grain size of the matrix decreases to 39 μm in Al₂O_3np/SiC_np/Al, which shows improvements of approximately 118% and 26% as compared to those of Al₂O_3np/Al and SiC_np/Al, respectively. X-ray Diffractometer (XRD) results confirm the presence of SiC_np and Al₂O_3np in hybrid nanocomposites. The dispersed SiC_np and Al₂O_3np are homogeneously distributed in the matrix and no clusters consisting of SiC_np and Al₂O_3np exist in the microstructure. Theoretical analyses also verify that there is little possibility for clusters to form in the melt. Good bonding between nanoparticles and Al is demonstrated. Neither cavities nor reaction products exist at the interface. The ductility and the strength of Al₂O_3np/SiC_np/Al are improved. The improvement in yield strength of Al₂O_3np/SiC_np/Al, in comparison with that of A356, is about 45%.

An interfacial nanocomposite layer was proposed to investigate the effect of SiC_nps on interfacial thermal resistance between Si and Al.

The high-temperature oxidation resistance of AISI 321 stainless steel used in solar thermal power heat exchangers determines its service life. In this study, aluminizing and subsequent laser shock peening (LSP) treatments were employed to improve the high-temperature oxidation resistance of AISI 321 stainless steel at 620 °C. These two treatments decreased the oxidation rate of AISI 321 steel. Specifically, the optimal oxidation resistance was observed in aluminized steel before oxidation for 144 h owing to the increased entropy of the LSP-treated specimen. After 144 h, LSP-treated steel achieved the best oxidation resistance because of the formation of a protective α-Al ₂ O ₃ film. Moreover, the large amount of subgrain boundaries formed on the aluminized layer of the LSP-treated samples could act as short-circuit paths for the outward diffusion of Al, facilitating the rapid nucleation of α-Al ₂ O ₃ . Meanwhile, the aluminized layer could isolate the contact between the oxidation environment and matrix, thereby decreasing the oxidation rate. Furthermore, the minimum oxidation parabolic constant was calculated for LSP-treated steel (6.45787 × 10 ⁻¹⁴ ), which was 69.18% and 36.36% that of aluminized and 321 steel, respectively, during the entire oxidation process. Therefore, the combination of aluminizing and LSP treatments can improve the high-temperature oxidation resistance of 321 stainless steel, providing a new idea for its surface treatment to achieve a long service life at high temperatures.