基于陶瓷纤维三维编织的织构涂层刀具及其界面结合机理研究

Coating preparation technology is the key technology bottleneck restricting the development of coated tools. The defects of thin coating thickness and weak interface bonding seriously restrict the wider application of coated tools. The anisotropy of mechanical properties of three-dimensional braided ceramic fiber reinforced composites is weaker than that of two-dimensional film materials and two-dimensional braided materials, and it becomes a candidate material for coated tools with high interfacial bonding strength. In this study, ceramic fiber three-dimensional braiding was introduced into tool development, and a texture coated tool with texture structure on the surface and three-dimensional braiding structure on the surface of the tool was prepared by hot pressing sintering technology, which provided a new way for the development of coated tool. Aiming at the problem of thinner thickness and weak interfacial bonding of coating, this project proposes a design method of texture coated cutters based on three-dimensional braiding of ceramic fibers, discusses the formation mechanism of texture coatings, optimizes material composition and texture coatings structure, establishes the influence rules of different three-dimensional braiding structures on orientation and distribution of ceramic fibers in texture coatings, and reveals the interfacial bonding mechanism test. The dry cutting performance of texture coated tool was studied, and the mechanism of the effect of texture coated tool on friction reduction and wear resistance was revealed. It has important theoretical significance and practical value to promote the development of high-speed cutting tool technology.

涂层制备技术是限制涂层刀具发展的关键技术瓶颈，涂层厚度薄和界面结合弱的缺陷严重制约了涂层刀具的更广泛应用。三维编织陶瓷纤维增强复合材料的力学性能各向异性较二维膜材料和二维编织材料减弱，成为具有高界面结合强度涂层刀具候选材料。本研究将陶瓷纤维三维编织体引入刀具研制中，利用热压烧结技术制备一种刀具表面具有织构结构和表层具有三维编织结构的织构涂层刀具，为涂层刀具的研制提供一条新途径。项目拟针对涂层厚度薄和界面结合弱的难题，提出一种基于陶瓷纤维三维编织的织构涂层刀具的设计方法，探讨织构涂层的形成规律，优化设计材料组成和织构涂层结构；建立不同三维编织结构对织构涂层内陶瓷纤维的取向和分布影响规律，揭示界面结合机理；试验研究织构涂层刀具的干切削性能，揭示织构涂层对刀具减摩抗磨性能的影响机制。这对促进高速切削刀具技术的发展具有重要理论意义和实用价值。

涂层刀具的涂层厚度薄，涂层结合弱的问题限制了涂层刀具在难加工材料加工中的应用，本研究提出将陶瓷纤维三维编织体引入刀具体系中，研制了一种具有高界面结合强度，表层为陶瓷纤维三维编织体，表层厚度大，表层具有残余压应力，且表面形成织构的织构涂层刀具。研究结果表明，放电等离子烧结是实现表面和内部材料不同情况下的织构涂层刀具材料的有效方法。烧结后，刀具表面自生成微织构，其平均深度为9.79 μm，平均宽度为10.21 μm；织构涂层厚度在100-200 μm之间，纤维交叉结合形成桥联网络结构。刀具表面残余压应力约为440 MPa，界面结合强度在907.4 MPa~1420.5 MPa，其抗弯强度、硬度、断裂韧性分别为1351.2 MPa、19.3 GPa、10.85 MPa·m1/2。由于表面微织构的形成，刀屑实际接触长度比名义接触长度降低了56%，切削力降低了32%，切削温度降低了12%，表面粗糙度低至1.0-1.2μm，切屑由螺旋屑转变为C型屑。在vc=300m/min，ap=0.2mm 和f=0.102mm/r条件下，刀具的切削寿命较均质刀具延长了30%以上。传统的表面织构是采用加工法在刀具表面引入微观结构阵列，其各结构单元互相独立、共同作用；而织构涂层刀具的表面织构单元因三维编织而彼此联接、共同作用。即使织构的某一单元失效，其周围相关纤维仍然联接、交错，抑制裂纹扩展，一方面可提高刀具切削性能，另一方面在切削过程中还具有良好的减摩作用。负责人以第一作者/通讯发表论文16篇，本项目均为第一标注，其中中科院1区12篇，2区2篇，3区1篇，中文EI1篇；授权发明专利6件，公开发明专利4件；获得中国商业联合会科学技术一等奖1项（第4位）；做大会报告2次，分组报告1次，获得会议优秀论文1次；毕业研究生5名，其中获得国家奖学金2人，省级优秀毕业生1人，攻读博士学位3人。