Al_2O_3/Cr_3C_2/(W,Ti)C陶瓷材料的力学性能及微观结构

MECHANICAL PROPERTIES AND MICROSTRUCTURE OF CERAMIC MATERIALS Al_2O_3/Cr_3C_2/(W,Ti)C

用热压烧结工艺在1 700 ℃,28 MPa保温保压30 min 及N2 气氛条件下,制备了添加不同含量Cr3C2和(W, Ti) C颗粒的Al2O3/Cr3C2/(W,Ti)C复合陶瓷材料。对复合陶瓷的力学性能进行测试。用环境扫描电镜、透射电镜和能谱分析仪对复合陶瓷的显微结构进行观察。结果表明:与纯Al2O3相比,70Al2O3/10Cr3C2/20(W,Ti)C复合陶瓷材料的显微组织更均匀细化,具有良好的综合力学性能,其断裂韧性自纯Al2O3 陶瓷的4.0 MPa·m1/2提高到8.92 MPa·m1/2。分析发现:其内部位错机制、纳米颗粒的淀析、裂纹扩展路径偏转、沿晶断裂、韧窝及解理撕裂等是材料断裂韧性提高的主要原因。

Ceramic materials Al_2O_(3)/Cr_3C_(2)/(W,Ti)C with different contents of Cr_3C_(2) and (W,Ti)C particles were fabricated by hot-pressing technique at 1 700 ℃ under 28 MPa for 30 min in N_(2) atmosphere. Mechanical properties of the ceramic materials were tested, and the microstructure was investigated by environment scanning electron microscope, transmission electron microscope and energy dispersive analysis using X-ray. Results indicate that, compared with Al_2O_(3) ceramic, the microstructure of the multiphase composite ceramic material 70Al_2O_(3)/10Cr_3C_(2)/20(W,Ti)C is more uniform and has good mechanical properties, especially the fracture toughness of the ceramic material increases from 4.0 MPa·m^(1/2) (pure Al_2O_(3) ceramic) to 8.92 MPa·m^(1/2), due to incorporation of the suitable contents of Cr_3C_(2) and (W,Ti)C particles. Analysis shows that the dislocations mechanism, nano-particles deposition, crack deflection, transgranular fracture, and curved cleavage strips are main reasons for increasing the fracture toughness of the ceramic materials.