Al <sub> 2 </ Sub> O <sub> 3 </ Sub> ¡¤ Of Zro <sub> 2 </ Sub> Metal Ceramics And Performance Research

Al₂O₃ based cermet is a new type of high temperature die materials due to good high temperature strength .At present, As its fracture toughness is low that limited their application in certain areas, so improving the fracture toughness of Al₂O₃ based cermet is the focus of research. Zirconia toughened Al₂O₃ based Cermet is an important way, In this study, Al₂O₃·ZrO₂ /W/Cr/Ni/Co, Al₂O₃ /W/Cr/Ni/Co, Al₂O₃/ZrO₂ /W/Cr/Ni/Co cermet were prepared by vacuum sintering and hot pressing sintering, the microstructure and mechanical properties of three kinds Al₂O₃ based cermet materials were examined in detail by means of metallographic analysis, XRD, SEM/EDS, TEM, SENB and other analytical tools. The fracture mechanism of cermet were study. Thermal shock resistanc performance and high temperature deformation behavior of Al₂O₃·ZrO₂/W/Cr/Ni/Co cermet were study by high temperature thermal shock experiment and hot compression experiment.Through the study, the following conclusions were obtained.(1) Using a vacuum sintering prepared Al₂O₃·ZrO₂/W/Cr/Ni/Co cermet relative density was 74.2%, Al₂O₃·ZrO₂/W/Cr/Ni/Co cermet prepared by hot-pressing sintering,its relative density was 97.4%. The experimental results show that hot-pressing sintering process was more excellent.(2) By hot-press sintering preparation of Al₂O₃·ZrO₂/W/Cr/Ni/Co cermet fracture toughness was 7.23 MPa·m^1/2, Compare with Al₂O₃/W/Cr/ Ni/Co, Al₂O₃/ZrO₂/ W/ Cr/ Ni/Co cermet materials, its fracture toughness improved 30%, indicating that Al₂O₃·ZrO₂/W/Cr/Ni/Co cermet has good fracture toughness. This is because in the cermet Al₂O₃·ZrO₂/W/Cr/Ni/Co to retain more of the tetragonal zirconia (t-ZrO₂), t-ZrO₂ phase transformation toughening effect of the increased fracture toughness of cermets.(3) Compare with Al₂O₃ W/ Cr/ Ni/ Co,Al₂O₃/ZrO₂/ W/ Cr/ Ni/ Co cermet, Al₂O₃·ZrO₂/W/Cr/Ni/Co cermet has a high thermal shock critical temperature (ATc=380℃), In the cycle AT (300℃) were water quenching by 35 times, no significant the expansion of cracks was no observed and The experimental results show it has better thermal shock resistance.(4) The high temperature deformation of Al₂O₃·ZrO₂/W/Cr/Ni/Co cermet was investigated by the high-temperature thermal simulation experiment, the experimental results shows that Al₂O₃·ZrO₂/W/Cr/Ni/Co Cermet has better high-temperature toughness, is was not easy to crack. The stress-strain equation of Al₂O₃·ZrO₂/W/Cr/ Ni/Co Cermet was established.