[en] Highlights: • The aging kinetic of the Be/6061Al composite was accelerated. • The formation of GP zone in Be/6061Al composite was suppressed. • Mg and Si elements segregated on the Be/Al interface. • β″ precipitated independently or precipitated along dislocations in matrix. The aging behavior of Be/6061Al composites cannot indiscriminately copy the aging behavior of the 6061Al matrix alloy. In this study, the aging behavior of Be/6061Al composite (62% mass fraction of Be) fabricated by powder metallurgy technique was investigated by Micro Vickers hardness measurements, HRTEM and DSC experiments. Subsequently, the corresponding precipitation mechanism was discussed in detail. It was found that Be/6061Al composite exhibited an accelerated age hardening phenomenon as high density dislocations were incorporated by Be particles. The aging precipitation sequence of Be/6061Al composite was similar to 6061Al alloy, but the formation of GP zone was suppressed which can be attributed to the decrease of vacancy concentration caused by Be/Al interfaces and the segregation of Mg and Si on Be/Al interfaces.

[en] SiC/Gr/Al composites were fabricated by squeeze casting with graphite volume fractions of 3-7% and particles size of 1, 6, 10, 20 and 70 μm. No Al₄C₃ brittle interfacial product could be detected by transmission electron microscopy. With increasing volume fraction and particle size of graphite, the tensile strength (σ_b) decrease from 420 to 235 MPa and the elastic modulus (E) decrease from 166 to 116 GPa. These changes were in close accordance with the linear function: E = 224σ_b + 61,695

[en] Highlights: •Beryllium is oxidized in a Na₂CO₃ electrolyte using DC micro-arc oxidation. •The coating consists of an inner barrier layer and an outer porous layer. •The coating shows improved corrosion resistance and insulation properties. •XPS and XRD indicate that the coating is crystalline BeO. -- Abstract: Beryllium was oxidized at a current density of 10 mA cm⁻² in a 0.5 M Na₂CO₃ (pH = 11.2) electrolyte to understand the micro-arc oxidation (MAO) process. Different oxidation stages were investigated by analysing the voltage–time responses and coating morphology. ‘Electric breakdown’ accompanied by sparks travelling across the metal/electrolyte interface occurs when the voltage rises above a certain point (∼202 V), leading to the formation of an off-white ‘ceramic-like’ BeO coating. The MAO coating consists of two layers—an inner barrier layer and an outer porous layer—and shows improved corrosion resistance and insulation properties. XPS and XRD indicate that the coating has a chemical composition of BeO and is crystalline. Further, corrosion resistance and insulation properties of the coating were estimated by EIS analysis.