Search

To improve the wear property of magnesium alloys, Zr-based amorphous composite coatings have been fabricated on AZ91D magnesium alloy by laser cladding using mixed powders Zr55Al10Ni5Cu30/SiC. The microstructure of the coating was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The wear resistance of the coatings was evaluated under dry sliding wear test condition at room temperature. The results show that the coatings mainly consist of amorphous and different crystalline phases. The coatings exhibit excellent wear resistance due to the recombination action of amorphous and different crystalline phases. The main wear mechanism of the coatings and the AZ91D sample are different, the former is abrasive wear and the latter is adhesive wear.

Pure Al2O3/AlB12/Al composite ceramic powders have been synthesized using high frequency induction heating method. This method starts from Al and B2O3 powder mixtures, after which Al2O3/AlB12/AlN composite ceramics were fabricated by hot-press sintering at 16000C for 2h under the protection of a N2 atmosphere. The bending strength and the fracture toughness of the ceramics were measured by the three-point bending method and the indentation fracture method, respectively. The results show that the pure Al2O3/AlB12/Al composite ceramic powders can be successfully synthesized by high frequency induction heating method. Al2O3 and AlB12 phases were formed by the liquid-liquid reaction mechanism and the liquid-solid reaction mechanism, respectively. The bending strength and the fracture toughness of the Al2O3/AlB12/AlN composite ceramics were 549.48MPa and 5.96MPa.m1/2, respectively. These values are 56.99% and 49% greater than those of the pure Al2O3 ceramic (350MPa and 4MPa.m1/2).