面向Ni/Fe功能梯度材料的铣刀长寿命服役机制

With the wide range application of Ni/Fe Functionally Graded Material (FGM) in major power equipment, a new problem is to be solved urgently. That is the extreme low durability of the milling cutter caused by FGM gradient physical properties, which seriously damages the quality of the machined surface of FGM. Therefore, this research project focuses on the milling tool wear mechanism and its long life during machining of Ni/Fe FGM. Firstly, the gradient evolution of Ni/Fe FGM physical properties is analyzed, and its constitutive mode is established. Secondly, the friction and wear characteristics of tool material against Ni/Fe FGM under real cutting environment are studied to obtain the critical load and temperature of adhesive wear, diffusive wear and oxidative wear. Afterwards, milling tool wear patterns against Ni/Fe FGM with different Ni/Fe ratios are studied to reveal the influence of FGM gradient on tool wear mechanism. Then, a parametric model of milling tool wear for Ni/Fe FGM is deduced, and the quantitative mapping relationship between Ni/Fe ratio, wear mechanism, cutting force-heat, cutting time and milling wear value is consequently figured out to predict tool life. Based on this, the long life tool control method for milling cutter against Ni/Fe FGM is proposed, and the optimal parameters sets are obtained. As a consequence, the results of this project can be the guideline to realize the long life service of milling tool when machining of Ni/Fe FGM.

随着Ni/Fe功能梯度材料在电力重大装备的大面积应用，由其物理性能梯度引发的铣削加工刀具耐用度过低，进而严重破坏被加工配合表面质量，是当前亟待解决的新问题。本项目以Ni/Fe功能梯度材料铣削加工刀具磨损机理与长寿命为研究对象，分析Ni/Fe功能梯度材料物理性能梯度演变规律，构建Ni/Fe功能梯度材料本构关系模型；研究类切削环境下Ni/Fe功能梯度材料与刀具材料摩擦磨损特性，获取发生粘结、扩散和氧化磨损的临界载荷与温度；研究不同Ni/Fe配比时铣刀磨损机理，获取材料物理性能梯度对铣刀磨损机理的影响规律；推导面向Ni/Fe功能梯度材料的铣刀磨损参数化模型，得到Ni/Fe配比、磨损机理、切削力热、切削时间与铣刀磨损量的定量映射关系，预测铣刀寿命；以此提出面向Ni/Fe功能梯度材料的分段调速控制铣刀长寿命方法，获取铣刀长寿命服役最优工艺参数集，为面向Ni/Fe功能梯度材料的铣刀长寿命服役奠定基础。

针对我国自主研制CAP1400百万千瓦汽轮机缸体汽密配合表面Ni/Fe功能梯度材料铣削加工质量差、刀具耐用度低的前沿技术痛点，本项目从Ni/Fe功能梯度合金的材料-性能一体化制备出发，以Ni/Fe功能梯度合金铣削加工过程中刀具长寿命服役为研究目标，以Ni/Fe功能梯度合金激光增材工艺的粉末分离机理、Ni/Fe功能梯度合金激光增材的低缺陷制备、微量润滑与微织构复合作用下铣削Ni/Fe功能梯度合金的刀具减磨机制等关键技术为研究切入点，提出面向Ni/Fe功能梯度合金的分段调速铣削工艺，构建了微量润滑环境下的突发型声发射信号聚类准确监测刀具磨损的新方法，实现了刀具磨损实时检测与精准评估，依托相关技术成果可大幅提升新一代汽轮机上、下半缸汽密配合表面的精度与质量，满足电力重大装备的极端化服役要求，为解决我国现阶段各行业电力短缺的问题奠定技术基础。主要研究成果如下：.1）通过研究Ni/Fe功能梯度合金激光增材工艺的粉末分离机理，建立了气固两相流体环境下的粉末动力学模型，提出了激光沉积制备配比精准调控方法；.2）通过分析Ni/Fe功能梯度合金激光增材过程中缺陷形成机理，建立了基于“粉末分离规避-熔道缺陷抑制-耗粉量最少”的激光增材工艺参数筛选流程，据此提出了面向Ni/Fe功能梯度合金激光增材的低缺陷制备工艺，所制备Ni/Fe功能梯度合金的抗拉强度463MPa、屈服强度434MPa、硬度271HV、伸长率13.75%，符合电力行业极端环境服役性能要求；.3）通过探究微量润滑与微织构复合作用下铣削Ni/Fe功能梯度合金的刀具减磨机制，建立了微织构与微量润滑复合作用下的刀-工界面减磨模型，基于Spearman相关系数模型，获取了Ni/Fe功能梯度合金的最优铣削参数，据此提出了面向Ni/Fe功能梯度合金的分段调速铣削工艺策略。