基于原子尺度相变模拟的氧化铝基陶瓷刀具及其增韧机理研究

Due to the limited varieties of alumina matrix ceramic tools for cutting quenched steel in the actual production, it is imperative to develop new alumina matrix ceramic tools. So far, the research on the phase analysis of ceramic tool materials is much less than the microstructure. It is very challenging to research the phase structure and conduct theoretical analysis, and much workload should be carried out during the study. In this project, alumina matrix ceramic tool materials will be studied deeply combining the atomic-scale computer simulation methods and the experimental methods. The relationship among phase composition, microstructure morphology and the mechanical properties of alumina matrix ceramic tool materials will be established. The theoretical guidance can be attained to the fabrication of alumina matrix ceramic tool materials with excellent mechanical properties and cutting performance. The molecular dynamics method will be used to simulate the formation of the core-shell structure and intermetallic compounds. The phase-field-crystal method will be used to simulate the mechanism of the phase transformation in which the metal binders join. The toughening and strengthening mechanisms will be explored. The experimental methods will be adopted to optimize the phase composition and phase structure of the material, so that the phase transition rule of alumina matrix ceramic tool materials during the sintering process can be explored. Combing with the results of computer simulation, an innovate kind of alumina matrix ceramic tool which can be qualified for high-speed cutting quenched steel will be developed.

目前实际生产中高速切削淬硬钢用氧化铝基陶瓷刀具种类较少，开发新型氧化铝基陶瓷刀具势在必行。迄今为止，对陶瓷刀具材料物相分析的研究较少，对物相结构探讨的理论和实验研究难度和工作量均较大。本项目旨在用原子尺度计算机模拟和实验研究相结合的方法对氧化铝基陶瓷刀具材料进行深入研究，建立物相组成和相结构、微观组织与力学性能之间的关联模型，为研制力学性能和切削性能优异的氧化铝基陶瓷刀具材料提供理论指导。用分子动力学法模拟芯壳结构及金属间化合物的形成机理，用晶体相场法模拟金属粘结剂参与相变的机制，探究增韧补强机理；实验优化材料的物相组成和相结构，探索氧化铝基陶瓷刀具材料烧结过程中的物相转变规律。结合计算机模拟结果，设计并研制一种能胜任高速切削淬硬钢的新型氧化铝基陶瓷刀具。

目前应用于淬硬钢高速切削的氧化铝基陶瓷刀具种类较少，本项目旨在开发新型氧化铝基陶瓷刀具材料。本项目采用实验和计算机模拟相结合的方法对氧化铝基陶瓷刀具材料的物相组成、微观组织、力学性能、切削性能等进行了研究。主要研究内容包括：（1）对Ti-Mo-C和Ni-Al-O体系进行了热力学优化与计算，得到了与芯壳结构和金属间化合物相关的多元相图；（2）综合研究了金属粘结剂Ni、Mo含量以及烧结温度和保温时间对于氧化铝基陶瓷刀具材料物相组成、微观组织和力学性能的影响，整理得到力学性能和物相结构的关联信息，优化组分配比和烧结工艺参数，研制了力学性能优异的氧化铝基陶瓷刀具材料；（3）将所研制的陶瓷刀具材料用于淬硬钢的加工，研究了陶瓷刀具的切削行为及抗磨损性能，判定了刀具材料与工件材料的匹配性；（4）针对陶瓷刀具切削用数控机床位置伺服系统的控制算法进行了研究，设计出两种基于无模型自适应控制的控制算法。本项目所研制的氧化铝基陶瓷刀具材料抗弯强度可达700.05MPa，维氏硬度可达31.096GPa，断裂韧度可达9.14MPa·m1/2，切削淬硬钢实验中抗磨损性能优于传统氧化铝基陶瓷刀具LT55，所设计的位置伺服系统控制器具有良好的动态性能和抗扰动能力，能够满足实际系统控制性能的需要。在下一步的模拟结果整理以及重复实验验证后，完善物相转变规律及增韧补强机理等相关理论，其结果能为研制力学性能和切削性能优异的新型氧化铝基陶瓷刀具的研发提供指导。