宏微纳多级仿生结构新型金刚石砂轮可控制备及磨削特性研究

Due to the superior characteristics in terms of cooling, lubrication and chip removal to grinding, the surface structured diamond grinding wheel has been widely used in grinding hard-and-brittle materials. However, the technological difficulties for the deteriorated surface roughness, severe wear and collapse in the structured region have never been solved. Its application and processing quality are greatly limited. In aiming to solve this problem, a novel macro-micro-nano bionic (MMNB) diamond grinding wheel is proposed by comparing the fractal similarity between the grinding process and the transpiration of the plant leaves. The controlled release and transient friction reduction mechanism of self-supplying nano-particles in the grinding regions are studied. The critical condition of brittle-ductile transition can be changed. Subsequently, the mechanism of chips-grains rally/dispersion effect and particle flocculation/cluster scale evolution are reveled. Based on the bionic structure of leaf veins, the fractal bionic model of micro groove/macro flow channel is established for optimizing laser ablated conditions. The synergistic effect and grinding characteristics of the MMNB diamond grinding wheel will be analyzed. Optimizing the surface functional structure of the grinding wheel, meanwhile, constructing the design/preparation of the MMNB diamond grinding wheel and the basic grinding theoretical system will be conducive to achieve the precision machining of hard-and-brittle material parts. The study and research achievement of this proposed project will promote the application of the surface structured diamond grinding wheel and improve the manufacturing level of hard-and-brittle material parts from the point of scientific significance and application value.

表面结构化金刚石砂轮以其冷却润滑排屑性好等特点在硬脆材料磨削加工中得到日益广泛的应用，但该方法目前仍无法突破表面粗糙度未降反升、结构化区域剧烈磨损甚至崩塌失效等技术瓶颈，其应用范围和加工质量受到极大限制。本项目通过对比砂轮磨削和植物叶片蒸腾作用的相似性，提出宏微纳多级仿生结构（MMNB）新型金刚石砂轮制备及磨削加工方法。研究磨削弧区自我供给纳米颗粒的可控释放、瞬时减摩机制，改变材料脆-延性域去除转变临界条件；揭示切屑-磨粒的团聚/弥散效应及颗粒团絮/群的尺度结构演化机制，建立微观沟槽/宏观流道叶脉分形仿生模型，确定叶脉仿生结构激光精准可控制备条件；重点研究MMNB协同效应及磨削特性，优化砂轮表面功能结构，构建MMNB金刚石砂轮设计制备及磨削加工基础理论体系，实现硬脆材料零件的高效低损伤加工。本项目对于促进表面结构化金刚石砂轮的推广应用、提升硬脆材料零件制造水平具有重要的科学意义和应用价值。

在金刚石砂轮磨削硬脆材料时，由于材料本身的高硬度、低韧性等性能，存在磨削区核心部位磨削液供给不足、排屑不流畅及磨削亚表面损伤严重等问题，是制约提高加工工件精度及表面完整性的瓶颈。项目组以叶脉结构为灵感，提出一种独特的分形分支砂轮。研究表明该仿生分形分支砂轮具有排屑流畅及磨削亚表面损伤小等特性，可获得高精度磨削效果。.（1）纳米结合剂金刚石砂轮微观沟槽/宏观流道创成机理方面，分析了纳米结合剂金刚石砂轮磨削过程切屑-磨粒的成分、数量、形状、尺寸以及理化性质，获取了磨粒特定磨损状态下典型形态特征及极限尺寸。在此基础上，研究了不同体积浓度MoS2/TiO2金刚石砂轮的磨削性能。研究结果表明纳米颗粒浓度影响磨削表面的润滑性能，纳米结合剂金刚石砂轮磨削力及砂轮表面粗糙度有效降低。为纳米结合剂金刚石砂轮微观沟槽/宏观流道创成机理的建立奠定了理论基础。.（2）宏微纳多级结构新型金刚石砂轮仿生设计与制备研究方面，根据植物叶片与砂轮两个模糊系统各相似元特征值的比值，获得植物叶片与砂轮磨削之间的相似元相似度。引入槽形分形角作为磨削分支几何参数，对不同角度的磨削性能进行了测试。研究结果表明分形角度影响仿生砂轮的表面，仿生分形分支砂轮的磨削力有效降低。为宏微纳多级结构新型金刚石砂轮仿生设计与制备提供了理论依据。.（3）宏微纳多级结构新型金刚石砂轮磨损机理及服役性能研究方面，搭建以皮秒激光器、光路传输系统、3D 振镜系统、高精度平面磨床等为主的 MMNB 新型金刚石砂轮磨削实验平台。提出了一种新的激光宏微组合结构磨削方法。研究了LMMCSG对磨削力比、表面质量和砂轮磨损的影响。结果表明激光烧蚀对砂轮烧蚀区以外的金刚石颗粒没有影响，在LMMCSG条件下可以获得更好的表面质量，同时也有效的降低了磨损，提高了砂轮的性能寿命。.研究成果为工程陶瓷、光学玻璃及半导体材料等硬脆难加工材料提供了一种新的加工方法，对推动我国高效磨削加工技术的发展有重要理论意义和应用价值。