An investigation into the microstructure and mechanical properties of V2AlC MAX phase prepared by microwave sintering

Abstract

The present study investigated the mechanical properties and microstructure of V2AlC MAX phase prepared by the microwave sintering process. The powders mixture of the V-Al-C system with the molar ratio of 2:1.5:1 was mixed through a mixer mill for 10 min in the ethanol media without any aggressive milling condition. The microwave sintering process was performed at the sintering temperatures of 1200, 1300 and 1400 °C without any soaking times and the protective atmosphere in the graphite bed. The XRD patterns showed the formation of the V2AlC max phase at the sintering temperature of 1200 °C with VC and Al2O3 compounds. In contrast, the sample sintered at 1300 °C displayed completely matched peaks with the reference pattern of the V2AlC MAX phase. Moreover, the related XRD patterns belonging to the specimen sintered at 1400 °C demonstrated the formation of VC and Al2O3 compounds as the dominant crystalline phases. The microstructure studies also showed the formation of the nano-layered MAX phases at the sintering temperatures of 1200 and 1300 °C. However, in the case of the sintering temperature of 1400 °C, the VC phases turned into the nano-blades shape after the cooling process. The highest bending strength of 189 ± 21 MPa was obtained for the specimen sintered at 1300 °C, while the highest Vickers hardness of 892 ± 15 Hv was calculated for the sample sintered at 1400 °C as the ceramic composite with the VC-Al2O3 composition.