基于微波烧结的亚微晶复杂刃形陶瓷刀具整体制造基础研究

In order to solve the problems of simple structure, low strength and toughness, and high price of the present ceramic cutting tools, microwave sintering is utilized to prepare the sub-crystal ceramic tools with complex edge based on the thermal and non-thermal effects of microwave. The prepared ceramic tools not only have complex edges but also the grain size is in sub-micron scale. The “structure-performance” of ceramic tools can be integrated manufactured efficiently by the method proposed by this project. In the present project, the distribution of electromagnetic field in microwave sintering furnace and ceramic, moulding process of complex three-dimension edge, microwave sintering dynamics of ceramic tool materials, and the cutting performance of sub-crystal complex edged ceramic tools will be studied. Based on the results, determine the optimal sintering area and configuration of heat-assist device, built the model between microwave power and self-heating rate of ceramic and the control model of mould pressing-sintering parameters based on the high precision molding of edge, reveal the microwave sintering mechanisms of ceramic tool materials, prepare the sub-crystal complex edged ceramic tools. Finally, get the optimal cutting parameters of ceramic tools and built the models of failure rate and cutting reliability of ceramic tools. The microwave sintering technology of ceramic tools proposed by this project will effectively increase the cost performance of ceramic tools. The complex edged ceramics will enlarge the application range and scale of ceramic tools in cutting field, promote high speed cutting technology, and will make important contributions to our high-end manufacturing.

现阶段陶瓷刀具结构简单、强韧度低和价格高等问题限制了其在切削加工中的应用范围和应用比例，本项目利用微波热效应和非热效应的独特烧结优势，通过对微波电磁场分布、三维复杂刃形刀具素坯成型工艺、微波烧结动力学和烧结工艺的研究，确定陶瓷自发热速率与电磁场的匹配关系及最优烧结区间、建立刃形高精度成型的模压—烧结工艺参数定量控制模型、获得晶粒生长冻结的烧结动力学“窗口”并揭示陶瓷刀具材料微波烧结机理，进而在低温快速条件下完成陶瓷刀具制备，使制备的陶瓷刀具在具有复杂刃形的同时，刀具材料微观组织处于亚微米尺度，保证刀具具有可靠的力学性能，实现陶瓷刀具“结构—性能”一体化高效制造。本项目研究的陶瓷刀具微波烧结技术可制备具有三维断屑槽型的陶瓷车刀片和复杂刃形的陶瓷铣刀片，将有效提高陶瓷刀具的性价比，扩大陶瓷刀具在切削加工中的应用，必将为我国高端制造业的发展做出重要贡献。

针对航空发动机镍基高温合金复杂构件高效加工的需求和当前采用传统烧结方法制备的陶瓷刀具结构简单无法应用于复杂构件高速切削的矛盾，研究基于微波烧结的新型复杂刃形陶瓷刀具制造技术，利用微波热效应（快速整体加热）和非热效应（加速传质）的独特烧结优势，使制备的陶瓷刀具在获得高精度复杂刃形的基础上，同时保证刃口具有高的力学性能，实现复杂陶瓷刀具“结构-性能”一体化高效制造。. 研究了微波电磁场在烧结腔和陶瓷试样内的分布规律，获得了辅热材料、样品加载方式等对温度场的影响，确定了批量化微波烧结刀具在烧结腔中的最优空间位置。研究了微波烧结工艺对氧化铝基陶瓷刀具材料致密化过程和微观组织演化的影响规律，揭示了陶瓷刀具材料微波烧结动力学和致密化机制，阐明了素坯成型工艺和微波烧结工艺对陶瓷刀具微波烧结收缩率的影响规律，获得了三维复杂刃形陶瓷刀具的素坯成型—烧结工艺控制策略。. 研制了三维槽型细晶Al2O3/SiCp/SiCw陶瓷刀具，与传统的平刀面陶瓷刀具相比，金属去除量提高了近2倍，加工表面粗糙度降低了32.5%。微波烧结的复杂刃形SiAlON陶瓷刀具在高速粗铣GH4169 (vc = 800 m/min, ap = 1.5 mm, fz = 0.12 mm/z)，刀具寿命比平刀面SiAlON陶瓷铣刀片提升了约71.4%，刀具没有崩刃破碎，刀具以粘结磨损导致的磨损失效为主，微波烧结的复杂刃形陶瓷刀具能够满足难加工材料高速切削要求。