Design and fabrication of Si3N4/(W, Ti)C graded nano-composite ceramic tool materials

作者：Tian, Xianhua; Zhao, Jun^*; Wang, Zhongbin; Liu, Xinhua

来源：Ceramics International, 2016, 42(12): 13497-13506.

DOI：10.1016/j.ceramint.2016.05.142

• Graded ceramic tool material
• Si3N4/(W, Ti)C
• Mechanical properties
• Microstructure
• Toughening and strengthening mechanisms

Si3N4/(W, Ti)C graded nano-composite ceramic tool materials with different thickness ratios and number of layers were fabricated by hot pressing technology. The flexural strength, fracture toughness and hardness of the sintered composites were tested and the microstructure and indention cracks were observed. The experiment results showed that the five-layer graded nano-composites with a thickness ratio of 0.2, which were sintered under a pressure of 30 MPa at 1700 degrees C in vacuum condition for 45 min, had the optimum comprehensive mechanical properties with a flexural strength of 1080.3 MPa, a hardness of 17.64 GPa, and a fracture toughness of 10.87 MPa . m(1/2). The formation of elongated beta-Si3N4 grains contributes to the favorable mechanical properties. The graded structure can induce residual compressive stress in the surface layer and enhance the mechanical properties. The strengthening and toughening mechanisms are a synergistic effect of intergranular and transgranular fracture, crack bridging and deflection.

• 出版日期2016-9
• 单位山东大学; 中国矿业大学（北京）