Synthesis, microstructure and mechanical properties of a MoAlB ceramic prepared by spark plasma sintering from elemental powders

Abstract

In this study, the high-pure MoAlB ceramic was successfully synthesized by the spark plasma sintering (SPS) method from elemental powders. The reaction process and intermediate products were determined by differential scanning calorimetry and X-ray diffraction analysis. It was established that the synthesis temperature could be as low as 800 °C via SPS route. Herein, the lattice constants of the synthesized MoAlB ceramic are confirmed to be a = 3.203 Å, b = 13.976 Å and c = 3.10 Å. It also can be established that the synthesized MoAlB ceramic by SPS method shows better enhanced comprehensive mechanical properties compared with the reported results. The Vickers hardness, compressive strength, flexural strength and fracture toughness are measured as 12.3 GPa, 1.67 GPa, 476.6 MPa and 6.5 MPa m1/2, respectively. No obvious delaminating deformation can be found on the fractured surfaces of MoAlB ceramic, despite the fact that the MoAlB ceramic has laminate structure. The transgranular and intergranular fracture play key roles during the compression and bending tests.