ZrO_2/Ti(C_7N_3)纳米复合陶瓷工模具材料的制备工艺

Preparation Techniques of ZrO_2/Ti(C_7N_3) Nanocomposite Ceramic Tool and Die Material

采用真空热压工艺制备ZrO2/Ti(C7N3)纳米陶瓷工模具材料,并研究热压工艺参数对材料力学性能和微观结构的影响。结果表明:当材料组分确定时,热压工艺参数对力学性能的提高与微观结构的改善起关键作用。在本研究的实验条件下,当烧结温度为1500℃、保温时间为30min、压力为30MPa时,ZrO2/Ti(C7N3)纳米陶瓷工模具材料的综合力学性能较好,其抗弯强度、断裂韧性和硬度分别为958MPa、7.48MPa·m1/2和13.09GPa。但对应单一力学性能的最优工艺参数有所不同。力学性能提高的原因在于热压工艺参数所导致的材料微观结构的改善。合适的工艺参数可使纳米陶瓷工模具材料的断裂模式转变为穿晶/沿晶断裂模式,有利于材料的增韧补强。

ZrO2/Ti(C7N3) nanocomposite ceramic tool and die material was prepared with the vacuum hot pressing technique. Effects of preparation techniques especially hot pressing parameters on the mechanical properties and microstructure were investigated. It is indicated that when the material compositions are determined the hot pressing parameters play an key role on the improvement of both mechanical properties and microstructure. Under the experimental conditions in the present study, the comprehensive mechanical properties of the ceramic nanocomposite is better when the sintering temperature, holding time and pressure is 1500 ℃, 30 min and 30 MPa, respectively. The flexural strength, fracture toughness and hardness reach 958 MPa, 7.48 MPa·m1/2 and 13.09 GPa. However the optimum hot pressing parameters corresponding to the single mechanical property index are different. The reason for the enhancement of the mechanical properties might be attributed to the improvement of the microstructure resulted from the optimum hot pressing parameters. It suggests that suitable hot pressing parameters can transfer the fracture mode to the transgranular/intergranular mode, which benefit the strengthening and toughening of the ZrO2/Ti(C7N3) nanocomposite ceramic tool and die material.