(1. 山东理工大学 机械工程学院，淄博255000;
2. 山东大学 机械工程学院，济南250061)
摘 要: 针对高速切削航空难加工材料镍基高温合金时对高性能刀具的迫切需求，采用热压烧结工艺，制备sialon梯度微纳米复合陶瓷刀具材料，研究烧结温度、保温时间、梯度层数对刀具材料力学性能及显微组织的影响。利用X射线衍射仪分析材料的物相组成，通过扫描电子显微镜和透射电子显微镜对微观形貌进行分析。结果表明:在1750 ℃烧结、压力35 MPa、保温60 min的条件下，成功合成了β-sialon。具有7层梯度结构的刀具材料在此工艺条件下可获得最优的力学性能:抗弯强度σf =840 MPa，表层维氏硬度HV为17.32 GPa，表层断裂韧性KIC = 8.96 MPa×m1/2，表层残余应力σr=-423 MPa，满足刀具材料的使用要求。微纳米颗粒的同时加入和合理的梯度结构是获得较高力学性能的主要原因。
关键字: 微纳米复合;残余应力;梯度陶瓷刀具;热压烧结;力学性能
（1. School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China;
2. School of Mechanical Engineering, Shandong University, Ji’nan 250061, China）
Abstract:In view of the urgent need for high-performance tools when high-speed machining aviation difficult-to-cut material nickel-based super alloy, a sialon graded micro-nano-composite ceramic tool material was prepared by hot-pressing sintering. The effects of sintering temperature, holding time and layer number on the mechanical properties and microstructure of the tool material were investigated. The phase identification was carried out by X-ray diffraction (XRD), and the fracture surface microstructure of the composites was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that β-sialon phase is formed at 1750 ℃ and 35 MPa for 60 min. The optimum mechanical properties of the ceramic material with 7 layer numbers are gotten:a flexural strength σf is 840 MPa, a surface layer Vickers hardness HV is 17.32 GPa, a surface layer fracture toughness KIC is 8.96 MPa×m1/2, a surface layer residual stress σr is -423 MPa, which meet the requirements for cutting tool materials. The high properties can be attributed to the addition of micro and nano grains and the suitable graded structure.
Key words: micro-nano-composite; residual stress; graded ceramic tool; hot-pressing; mechanical property
