仿生结构复合陶瓷刀具材料力学性能及显微结构

Microstructure and Mechanical Properties of Biomimetic Composite Ceramic Tool Materials

针对不同烧结条件及TiC/WC组分比,采用热压烧结工艺制备出三层仿生结构复合陶瓷刀具材料。测试了仿生结构复合陶瓷材料力学性能,并对材料断口形貌和裂纹扩展进行了观察分析。结果表明:仿生结构复合陶瓷刀具材料抗弯强度达870 MPa,维氏硬度达21.83 GPa,断裂韧性达7.56 MPa·m^(1/2),比SG4均质陶瓷刀具材料性能有所提高。断口形貌显示仿生结构复合陶瓷刀具材料较SG4均质刀具材料晶粒细密,晶粒尺寸呈现多尺度特征。材料断裂模式为穿晶断裂和沿晶断裂混合型。仿生结构复合陶瓷材料表面裂纹扩展呈现偏转和分叉。裂纹穿过材料界面扩展时有明显偏转现象。

According to different sintering conditions and TiC/WC composition ratio, three-layer biomimetic composite ceramic tool materials were prepared by hot pressing sintering process. The mechanical properties of the biomimetic composite cera mic materials were tested, and the fracture surface morphology and crack propagation were analyzed. The flexural strength, Vickers hardness and fracture tou ghness are 870 MPa, 21.83 GPa, and 7.56 MPa·m1/2, which are higher than those of SG4 homogeneous ceramic cutting tool material. Section morphologies show that the biomimetic composite ceramic material has finer microstructure than SG4 ceramic cuttin g tool material, and the grain size shows multi-scale characteristic. Fracture surfaces demonstrate a transgranular/intergranular mode. The crack propagation path of the surface layer shows crack deflection and bifurcation of the crack tip. The crack is also deflected as crack passing through the bimaterial interface.