石墨烯增韧Al2O3/Ti(C,N)纳米复合陶瓷刀具材料的制备及其微观结构分析

摘要

采用热压烧结工艺制备了石墨烯增韧Al2O3/Ti(C,N)纳米复合陶瓷刀具材料,测试了石墨烯垂直于(VHPD)和平行于热压方向(PHPD)上的力学性能,研究了石墨烯取向对其力学性能和微观结构的影响.测试结果表明石墨烯具有明显的增韧补强作用,石墨烯的取向对刀具材料的抗弯强度具有明显的各向异性.当石墨烯含量为0.75 vol%时,VHPD方向上的抗弯强度达到667 MPa,较未添加石墨烯的组分提高了16%;PHPD方向的抗弯强度为575 MPa,断裂韧性达到7.1 MPa·m1/2.采用扫面电子显微镜(SEM)对材料进行了微观结构分析,结果表明石墨烯拉断和拔出是其主要增韧形式.石墨烯在基体材料中具有明显取向特征,石墨烯片层之间相互平行,且垂直于热压方向.%Graphene toughened Al2O3/Ti(C,N) nanocomposite ceramic cutting tool material was fabricated by the hot-pressing method. Its mechanical properties in the direction of being vertical or parallel to the hot-pressing direction(VHPD or PHPD,respectively) were tested. The effects of the orientation of graphene on its mechanical properties and microstructure were studied.Results show that graphene has obvious reinforcement effect on the matrix material,and its orientation has significant effect on the anisotropy of material's flexural strength. When graphene is added by 0.75 vol%,the flexural strength of VHPD is 667 Mpa,which is improved by 16% from the value without graphene.The flexural strength and fracture toughness of PHPD is 575 Mpa and 7.1 Mpa·m1/2,respectively.Scanning electron microscope(SEM) indicates that the main toughening form of graphene is its breakage and extraction.Furthermore,graphenes are parallel to each other and perpendicular to the hot-pressing direction.These might give the primary explanation for the mechanical property anisotropy.