Effect of Mo Content on In-Situ Anisometric Grains Growth and Mechanical Properties of Mo2FeB2-Based Cermets.

Mo2FeB2-based cermets have wide applications in fields of wear resistance, corrosion resistance and heat resistance due to their simple preparation process, low-cost raw materials, and prominent mechanical properties. Herein, Mo2FeB2-based cermets with xMo (x = 43.5, 45.5, 47.5, 49.5, wt.%) were prepared by means of the vacuum liquid phase sintering technique. Investigations on the microstructure and mechanical properties of Mo2FeB2-based cermets with Mo addition were performed. Experimental results show that, with Mo content increasing, the average particle size decreases gradually, revealing that the grain coarsening of Mo2FeB2-based cermets is controlled by interface reaction. In addition, Mo2FeB2 grains gradually transform from an elongated shape to a nearly equiaxed shape. The improvement of Mo2FeB2 hard phase on the morphology is mainly due to the inhibition of solution-precipitation reaction by increasing Mo. Furthermore, the relative density of cermets decreases due to the reduced Fe content. When Mo content is 47.5 wt.%, a relatively small grain size of Mo2FeB2 is obtained (about 2.03 µm). Moreover, with the increase in Mo content, hardness and transverse rupture strength (TRS) of Mo2FeB2-based cermets increase firstly and then decrease. Whereas, with increasing Mo content, the fracture toughness deteriorates gradually. When Mo content is 47.5 wt.%, the comprehensive mechanical properties of cermets are the best. The optimal raw material ratio for the preparation of Mo2FeB2-based cermets in this study is determined to be 47.5 wt.% Mo-6.0 wt.% B-Fe.