Microstructure and mechanical properties of spark plasma sintering produced ZrC–Mo composites

Abstract

The fabrication of ZrC–Mo composites with (10–25 vol. %) Mo content using a spark plasma sintering at 1750 °C under 35 MPa was investigated in this research. The effects of adding various Mo contents on the composites were also examined. The microstructure and phase analysis were investigated by scanning electron microscopy, x-ray diffractometer, and energy dispersive spectroscopy. Microscopic analysis revealed that the addition of metal Mo resulted in making the ceramic particles of ZrC finer, the sintered products denser, and the sintering conditions softer. Moreover, a continuous solid solution forms in the composite as the Mo content rises, the (Zr, Mo)C and (Zr, Mo)2C start to generate, and thus solid solution strengthens the material. The addition of metal Mo reduced the grain size of the ceramic composite and also lead to fine-grain strengthening. With a relative density of 97.53%, a Vickers hardness of 23.88 GPa, and a flexural strength of 317.55 MPa, the composite possessed the best properties when the molybdenum volume fraction reaches 15 vol. %. The synergistic effect of fine grain strengthening and solid solution strengthening improved the mechanical behavior of the composite.