Preparation and characterization of highly flexible Al₂O₃/Al/Al₂O₃ hybrid composite

The natural brittleness of oxide ceramics heavily inhibits their more extensive applications. In present research, a highly flexible Al₂O₃/Al/Al₂O₃ hybrid composite was fabricated by employing plasma electrolysis oxidation to in situ grow alumina layers on Al foil, in which an outside layer of nanostructured polycrystalline oxide ceramic was composed of nanosized grains with the size of around 17 nm. Due to shear band formation, nanosized circle bubbles prolonging the crack path, grain rotation, and deformation, the fabricated Al₂O₃/Al/Al₂O₃ hybrid composite contains no observable cracks even after being bent on a cylindrical bar with a curvature of 1.5 mm. The composite exhibits alumina stiffness at the elastic stage and aluminum ductility during plastic deformation, which provides high flexibility with the well-integrated properties of the components. In a synergistic interaction, the alumina on the outside exhibited a strain of 0.33% at room temperature, which was higher than optimum value of 0.25% presented by reported most flexible oxide ceramics. With the unique characteristics and properties, the Al₂O₃/Al/Al₂O₃ composite demonstrates a great potential for various engineering applications.