石墨烯纳米片增韧Al_2O_3基纳米复合陶瓷刀具材料

Alumina-based nanocomposite ceramic cutting tool materials toughened by graphene nanoplates

以石墨烯纳米片作为增强相,采用热压烧结工艺制备石墨烯纳米片增韧Al_2O_3基纳米复合陶瓷刀具材料。进行石墨烯纳米片分散实验,研究石墨烯纳米片添加量对刀具材料断裂韧度、抗弯强度和硬度的影响,观察其微观结构和形貌。结果表明:聚乙烯吡咯烷酮(PVP)为石墨烯纳米片的优选分散剂,当PVP添加量为石墨烯纳米片质量的60%时,分散效果最佳;当石墨烯纳米片添加量为0.75%(体积分数)时,刀具材料的断裂韧度和抗弯强度分别达到7.1MPa·m^(1/2)和663MPa,与未添加石墨烯纳米片的组分相比分别提高了31%和15%;石墨烯纳米片呈卷曲状结构弥散分布于基体材料中,其增韧机理为石墨烯纳米片拉断、拔出和裂纹偏转。与未添加石墨烯的刀具相比,添加石墨烯纳米片的刀具的主切削力、切削温度和前刀面摩擦因数明显降低,表现出良好的减摩、耐磨性。

Graphene nanoplates(GNPs),as toughening phase,toughened alumina-based nanocomposites ceramic cutting tool materials were fabricated by hot-pressing technology.The dispersing experiment of the GNPs was performed.The effects of different GNPs contents on the fracture toughness,flexural strength and hardness of the as-sintered ceramic cutting tool materials were investigated.The microstructure and morphology of GNPs were also observed.The results show that polyvinyl pyrrolidone(PVP) is the optimized dispersant of GNPs.When PVP addition is the 60%(mass fraction) of GNPs,the GNPs dispersion effect is the best.When GNPs addition is 0.75%(volume fraction),the fracture toughness and flexural strength of the cutting tool material reach up to 7.1MPa·m1/2 and 663MPa,which increase by 31% and 15% compared with that without GNPs addition cutting tool material.The crimped GNPs disperse well in the matrix material.The main toughening mechanisms include GNPs rupture,GNPs pull-out and cracks defection.Comparing with no GNPs addition cutting tool material,GNPs toughened cutting tool material shows lower main cutting force,cutting temperature and rake friction coefficient,and better wear resistance.