(1. 山東理工大學(xué) 機(jī)械工程學(xué)院，淄博255000;
2. 山東大學(xué) 機(jī)械工程學(xué)院，濟(jì)南250061)
摘 要: 針對高速切削航空難加工材料鎳基高溫合金時(shí)對高性能刀具的迫切需求，采用熱壓燒結(jié)工藝，制備sialon梯度微納米復(fù)合陶瓷刀具材料，研究燒結(jié)溫度、保溫時(shí)間、梯度層數(shù)對刀具材料力學(xué)性能及顯微組織的影響。利用X射線衍射儀分析材料的物相組成，通過掃描電子顯微鏡和透射電子顯微鏡對微觀形貌進(jìn)行分析。結(jié)果表明:在1750 ℃燒結(jié)、壓力35 MPa、保溫60 min的條件下，成功合成了β-sialon。具有7層梯度結(jié)構(gòu)的刀具材料在此工藝條件下可獲得最優(yōu)的力學(xué)性能:抗彎強(qiáng)度σf =840 MPa，表層維氏硬度HV為17.32 GPa，表層斷裂韌性KIC = 8.96 MPa×m1/2，表層殘余應(yīng)力σr=-423 MPa，滿足刀具材料的使用要求。微納米顆粒的同時(shí)加入和合理的梯度結(jié)構(gòu)是獲得較高力學(xué)性能的主要原因。
關(guān)鍵字: 微納米復(fù)合;殘余應(yīng)力;梯度陶瓷刀具;熱壓燒結(jié);力學(xué)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
