Al_2O_3-ZrO_2/W/Cr/Ni/Co金属陶瓷的断裂韧性

Fracture Toughness of Al_2O_3-ZrO_2/W/Cr/Ni/Co Cermets

以Al2O3-ZrO2复合粉末、W、Cr、Ni、Co粉末为原料,采用热压烧结工艺制备了性能优良的Al2O3-ZrO2/W/Cr/Ni/Co金属陶瓷复合材料。通过SEM,EDS,XRD等手段分析其微观组织,单边梁开口法(SENB)测量其断裂韧性。实验结果表明在1320℃,20MPa条件下热压烧结制备的Al2O3-ZrO2/W/Cr/Ni/Co金属陶瓷的断裂韧性为7.16±0.4MPa.m1/2,硬度为83.3HRA,横向断裂强度为540MPa,相对致密度为97.4%;对维氏压痕下裂纹扩展进行了分析,其增韧机理为延性金属对裂纹的桥梁作用和氧化锆相变增韧,在裂纹通过时硬质相以沿晶断裂为主。

Al2O3-ZrO2/W/Cr/Ni/Co cermets were prepared by using a hot-pressing process with Al2O3-ZrO2 composite powder,and W,Cr,Ni,Co powders.Microstructure of Al2O3-ZrO2/W/Cr/Ni/Co cermets was studied by using scanning electron microscopy（SEM） in combination with energy dispersive spectrometry（EDS）,X-ray diffractometry（XRD）.The fracture toughness of Al2O3-ZrO2/W/Cr/Ni/Co cermets was studied by using single edge notch beam（SENB）.Experimental results show that Al2O3-ZrO2/W/Cr/Ni/Co cermets were achieved at 1320℃ with a pressure of 20MPa,the fracture toughness was 7.16±0.4MPa·m^1/2,the hardness was 83.3HRA,the flexural strength was 540MPa and the relative density was 97.4%.Vickers indentation crack propagation of the cermets was studied,results show that toughening mechanism is ductile metal binder phase of crack bridge and the crack deflection due to the t-ZrO2 to m-ZrO2 transformation.The typical fracture mode of the hard phase is intergranular.