表层实时增韧抑制硬脆材料磨削加工崩裂损伤机理及关键技术

Micro cracks and micro porous existing in surfaces/subsurface of hard-brittle materials are the main causes inducing edge chipping in grinding. Improving the surface fracture toughness of hard-brittle materials by toughness agent in real-time is a new idea to reduce or eliminate edge chipping. The edge chipping of engineering ceramics as a typical hard-brittle material is studied in this research, the wetting performance of engineering ceramics is taken as evaluation index, the orthogonal experiment method is used to select the main factors influencing wetting ability of hard-brittle materials, and the preparation and infiltration process of toughness agent are optimized. The capillary phenomenon, adsorption behavior and interfacial chemical reaction characteristics of hard-brittle materials are studied, and the infiltration mechanism of the toughness agent is discussed, which could be used to guide the improvements of preparation process and infiltration process of toughness agent. Quasi-static single crystal indentation experiment system and single particle scratching test system are built to study the damage regulars and mechanisms of edge chipping worked by toughness agent. The mechanisms toughening surface/subsurface fracture toughness of hard-brittle material by toughness agent are researched, which could be used as a guide to optimize the grinding process rules. The research results will help to reduce or eliminate edge chipping and improve processing qualities of hard-brittle materials.

表层/近表层的微裂纹、微空隙是诱发硬脆材料磨削过程中产生崩裂损伤的关键因素。通过增韧剂实时改善硬脆材料磨削过程中的表层断裂韧性，提高材料自身抵抗裂纹扩展的能力，是减轻甚至消除崩裂损伤的新思路。以典型硬脆材料工程陶瓷的崩裂损伤为研究对象，以润湿性能为评价指标，应用正交实验法筛选出影响硬脆材料润湿性能的主要因素，优选出增韧剂的配制工艺和浸润工艺。研究硬脆材料浸润过程中的毛细现象、吸附作用和界面化学反应特征，揭示增韧剂的增韧机理，并以此指导增韧剂配制和浸润工艺的改进。建立增韧剂作用下准静态单晶压痕崩裂损伤实验系统、单颗粒划痕实验系统，研究增韧剂作用下的硬脆材料崩裂损伤规律，并揭示其材料去除机理。建立磨削参数与增韧剂润湿性能之间的关联，并以此为依据优化出合适的磨削工艺规程。研究成果将减轻或消除硬脆材料磨削加工的崩裂损伤程度，提升加工品质。

表层、近表层的微裂纹、微空隙是诱发硬脆材料磨削过程中产生崩裂损伤的关键因素。通过改善硬脆材料磨削过程中的表层断裂韧性，提高材料自身抵抗裂纹扩展的能力，是减轻甚至消除崩裂损伤的新思路。以接触角、浸润时间、浸润深度、平均浸润速率为润湿性能评价指标，以固化时间为固化速率评价指标，通过全因素实验优化出了一种能在碳化硅陶瓷表层快速润湿与固化的增韧剂配方。应用扫描电子显微镜高性能压汞仪单晶压痕力学试验检验了增韧剂作用下的性能特征，应用磨削实验验证了增韧剂对崩碎损伤的作用效果。结果表明：所制备增韧剂可使得碳化硅陶瓷的表层硬度降低约25%；同一边缘距离下，可使得碳化硅陶瓷产生崩碎损伤时的临界载荷提升约14.9%，压头位移提升约58.5%；增韧剂可有效降低碳化硅陶瓷磨削加工后的出口崩碎损伤与表面损伤，显著提升其磨削加工质量。.研究成果发表论文7篇，申报国家发明专利8项（授权3项），参加国内举办的学术会议5次，培养硕士研究生1名，达到了预期效果。.