基于石墨烯与球形氧化铝强化导热协同效应的新型复合砂轮

Grinding burn damage occurs constantly in high efficiency deep grinding of difficult-to-cut materials such as nickel-based superalloy, which must be inhibited by the thermal generation and persuasion in the grinding arc area. With the excellent characteristics of the thermal conductivity and mechanical properties of the graphene, a new type of composited wheel based on synergy effect between graphene and Al2O3 particles on strengthening heat conduction is proposed, which aims to improve the wear-resistance and anti-friction performance of grinding wheel in case of reducing the thermal generation in the grinding arc area. Moreover, based on the synergistic effect in strengthening heat conduction between graphene and spherical Al2O3 particles it will effectively lead the grinding heat from the grinding wheel and reduce the proportion into the workpiece, and thus inhibiting the thermal damage. The objectives of this project are given as follows: Firstly, based on the multi-phase enhanced composite material theory, it is to explore the formation mechanism of Ag-Cu-Ti alloy with graphene, CBN abrasives, and alumina particles. Then, it is to reveal the mechanism of reducing friction between the wheel and workpiece surface by inducing graphene into the composited bond, and to explore the synergistic effect between graphene and spherical Al2O3 in strengthening heat conduction. Finally, it is to develop a heat transfer model during the high efficiency deep grinding process based on the heat transfer theory, and it can be used to explore the synergy effect of the strengthening heat conduction on the material removal mechanisms and wheel erosion mechanisms during the high efficiency deep grinding process. The purpose of this project is to lay a scientific foundation for the development of high performance composited grinding wheel, which has a great theoretical significance for improving the technical level of high efficiency green grinding in the field of aeroengine difficult-to-cut materials.

镍基高温合金等难加工材料在高效深切磨削中极易造成磨削烧伤，必须从控制弧区磨削热的产生与疏导两方面来抑制烧伤。凭借石墨烯优良的导热及力学性能，本项目提出基于石墨烯与球形氧化铝协同强化导热的新型复合砂轮的构想，旨在通过引入石墨烯提高砂轮耐磨减摩性能，降低弧区磨削热的产生；同时基于石墨烯与球形氧化铝在强化导热中的协同效应，有效将磨削热从砂轮中疏导出去，降低进入工件的比例，抑制烧伤。主要研究内容包括：依据多元相增强复合材料理论，探索铜锡钛合金与石墨烯、磨粒、氧化铝陶瓷球颗粒之间结合界面的形成机理；揭示石墨烯提高结合剂耐磨减摩机理及石墨烯与球形氧化铝在强化传热中的协同效应；基于传热学反问题建立高效深切磨削过程传热模型，揭示协同强化传热效应在高效深切磨削过程中的作用机理及砂轮磨损机理。本项目旨在为研制高性能复合砂轮奠定科学基础，对于提高航空发动机难加工材料高效绿色磨削领域工具技术水平具有重要理论意义。

镍基高温合金等难加工材料在高效深切磨削中极易造成磨削烧伤，必须从控制弧区磨削热的产生与疏导两方面来抑制烧伤。凭借石墨烯优良的导热及力学性能，本项目提出基于石墨烯与球形氧化铝协同强化导热的新型复合砂轮研究，旨在为研制高性能复合砂轮奠定科学基础，对于提高航空发动机难加工材料高效绿色磨削领域工具技术水平具有重要理论意义。项目研究重要成果如下：.（1）石墨烯增强多孔砂轮磨料层强度与耐磨减摩性研究。研究结果表明，石墨烯增强复合结合剂与CBN磨粒发生扩散和化学反应，保证了磨削过程中结合剂对磨粒的牢固把持；结合石墨烯含量对磨料层节块抗弯强度影响分析和磨料层节块试样的摩擦磨损试验结果，优化石墨烯在磨料层中的含量为0.01wt.%，既保证其对磨料层整体抗弯强度的增强效果，又起到一定的减摩效果。.（2）石墨烯增强多孔复合砂轮磨削性能与磨损特性。开展了钛合金高效深切磨削试验研究，从磨削力、磨削温度、工件表面质量等方面评价了石墨烯增强多孔复合CBN砂轮的磨削性能；通过砂轮磨损特性研究发现，砂轮表面相同位置处磨粒与孔隙交替出现，砂轮表面的孔隙面积与磨粒粒数保持着动态平衡，该新型砂轮具备一定的自锐能力。.（3）石墨烯增强多孔复合砂轮磨削传热研究。建立了钛合金磨削温度场有限元仿真模型，可实现磨削过程三维瞬态温度场的可视化；试验验证后发现，仿真获得的磨削温度与试验获得的磨削温度之间的误差仅在4%-8%，能够比较精确地预测磨削温度；对高效深切磨削热分配系数进行了计算，结果显示传入工件的热量比例介于2%-6%之间，相对于陶瓷结合剂CBN砂轮（4%-8%）以及普通刚玉磨料砂轮（25%-62%），项目研制的石墨烯增强复合CBN砂轮的热分配系数更低，达到了预期效果。