CBN/铁基球形复合磁性磨粒制备机理及其难加工材料曲面光整性能研究

In order to meet the urgent demand of magnetic abrasive particles for high efficiency magnetic abrasive finishing high-performance curved surface of difficult-to-machine material, a new method, named high-speed mixing powder gas flow with ultrasonic atomization to fabricate CBN/iron-based spherical composite magnetic particles was proposed, and the experimental research of magnetic abrasive finishing complex curved surface of difficult-to-machine material is carried out. By means of integrated control technology of activating design of ferromagnetic matrix with high magnetic permeability, high-speed mixing powder gas flow, ultrasonic atomization with tightly coupled, rapid solidification, as well as follow-up heat treatment, the technical conundrum can be solved for the system of CBN/ iron-based composite in which the compatibility and wetting of between iron-based matrix phase and CBN phase is very bad. .Through the flow field characteristics research of three-phase flow of gas, liquid and solid in the process of ultrasonic atomization, special design of atomizing nozzle, optimizing control of process parameters, the wetting combining mechanism and the influence law in the process of preparation for the CBN/iron-based spherical composite magnetic particles can be discovered; and its formation mechanism can be proved; then the active control of morphology and performance consistency can be achieved. And then the CBN/iron-based spherical composite magnetic particles with high-performance and long-life will be obtained. In order to evaluate the performance of the new CBN/iron-based spherical composite magnetic particles, the test of magnetic abrasive finishing for the complex curved surface of difficult-to-machine material is carried out; and the optimizing match of between the new CBN/iron-based spherical composite magnetic particles and difficult-to-machine material is discovered. Furthermore, it is investigated into its mechanism and regularity. To sum up, the relevant research findings in this project will lay the theoretical and technical foundations for magnetic abrasive finishing of CBN/iron-based spherical composite magnetic particles to the difficult-to-machine material parts with complex shapes.

针对难加工材料高性能复杂曲面高效磁力光整加工对磁性磨料的迫切需求，本项目提出高速混粉气流超声雾化法以及辅助技术制备CBN/铁基球形复合磁性磨粒的新方法，并将其进行难加工材料曲面磁力光整加工研究。采用高磁导率铁基体成分活化设计、高速混粉气流、超声紧耦合气雾化、快速凝固及后续热处理综合控制技术，解决CBN/铁基复合体系中两相很难相容的关键科学问题。通过对雾化过程中气、液、固三相流流场特性研究、雾化喷嘴专门设计、工艺参数优化控制，探索CBN/铁基复合体系中两相之间的润湿结合机理及影响规律；探明球形磁性磨粒形成机制；实现形貌和性能一致性主动控制；获得高性能、长寿命CBN/铁基球形复合磁性磨粒。通过难加工材料曲面磁力光整试验研究，检验其性能；获得磁性磨粒与工件材料之间的最佳适宜条件；研究材料去除机理和加工表面形成规律；为CBN/铁基球形磁性磨粒在磁力光整难加工材料曲面中的广泛应用奠定理论和技术基础。

针对难加工材料高性能复杂曲面高效磁力光整加工对磁性磨料的迫切需求，本项目提出并研究了一种高速混粉气流雾化快凝制备CBN/铁基球形复合磁性磨料的新方法，并将其应用于难加工材料曲面的磁力光整加工中。基于雾化快凝理论和复合材料性能可设计性，研制了陶瓷/铁基磁性磨料粉末制备装置；进行了铁磁性基体成分设计，确定了基体配方；对磁性磨料制备试验方案进行了合理的试验设计，研究确定了工艺路线，研制了性能优异的CBN/铁基球形复合磁性磨料。借助扫描电镜、能谱仪、物相分析仪等对所制备的磁性磨料进行了微观形貌、界面微结构、组织成分、铁基体晶粒形态的检测与分析；研究了CBN/铁基球形复合磁性磨料两相之间的润湿结合机制；解决了CBN/铁基复合材料体系中两相之间很难相容的关键科学问题；揭示了其润湿结合机理和影响规律；获得了性能优异的CBN/铁基球形复合磁性磨料制备的工艺方法。. 根据理论分析和模拟仿真，研制了专用开槽磁极，建立了CBN/铁基球形复合磁性磨料磁力光整难加工材料试验系统。采用所制备的磁性磨料对镍基高温合金、钛合金、氧化锆陶瓷等典型难加工材料进行了磁力光整加工工艺试验；研究了工艺参数与材料去除量、表面粗糙度、表面残余应力、显微硬度等表面质量指标之间的映射关系；揭示了CBN/铁基球形复合磁性磨料磁力光整加工难加工材料曲面两者之间的交互作用机理和材料去除规律； 获得了CBN/铁基球形复合磁性磨料磁力光整加工难加工材料的工艺基础数据和光整加工方法。该项目的研究，对于高效率、低成本地制备优异性能CBN/铁基球形复合磁性磨料以及提高难加工材料曲面光整加工表面质量和加工效率具有重要理论意义和工程应用价值。