An investigation into the microstructure and mechanical properties of V4AlC3 MAX phase prepared by spark plasma sintering

Abstract The present work investigated the effect of spark plasma sintering of V4AlC3 MAX Phase on the microstructure and mechanical properties. Accordingly, Vanadium, Aluminum and carbon-black powders were mixed through a high energy mixer mill for 10 min in an ethanol medium. The direct inserted mixture of Al-V-C systems in a graphite mold was spark plasma sintered at 1350 °C with the initial and final applied pressure of 10 and 30 MPa at the vacuum condition of 20 Pa. The XRD investigations demonstrated the V4AlC3 crystalline phase along VC and Al2O3 as the side-effect reaction products. The microstructure analyses further indicated a perfect lath-like MAX phase with an almost proper growth. The FESEM micrographs of the prepared sample also indicated the formation of the V4AlC3 MAX phase with the lath-like shape. The fracture surface of the specimen also displayed deformed and separate lath-like phases as a result of the bending test. The different loads used for the hardness test demonstrated a deformation zone around the mark indentation. By increasing the applied load in the hardness test, the deformed area was enhanced. The prepared FESEM images from the deformed area showed different crack propagation mechanisms such as separation and branching, deflection, bridging, particles pulling out and breaking. 389 ± 19 MPa of bending strength and 6.74 ± 0.12 GPa of Vickers hardness were obtained for the prepared sample along the almost full densification as 99% of theoretical density.