强流脉冲电子束辐照WC-Co硬质合金表面纳米碳粒子析出行为及摩擦学性能研究

项目名称： 强流脉冲电子束辐照WC-Co硬质合金表面纳米碳粒子析出行为及摩擦学性能研究

项目编号： No.51471043

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 郝胜智

作者单位： 大连理工大学

项目金额： 80万元

中文摘要： 现代加工制造业对WC-Co硬质合金的材料性能提出更高要求，表面硬度低、耐磨性差是现有硬质合金工具(WC晶粒>0.3μm)的主要问题。高能束表面改性能有效提高WC-Co硬质合金的使役性能，且无膜基结合强度问题，但由于设备因素使应用研究受到限制。申请人利用自行研制的强流脉冲电子束装置进行WC-Co硬质合金表面改性，发现WC晶粒原位弥散析出纳米碳粒子，将耐磨性提高十几倍，但对于碳粒子的析出及减磨机制尚不清楚。基于此，本项目拟针对强流脉冲电子束辐照WC-Co硬质合金表面纳米碳粒子的析出行为及其对摩擦学性能的影响进行深入研究，包括WC晶粒的纳米碳粒子析出条件和组织演化规律；纳米碳粒子在摩擦磨损过程中的结构变化和迁移行为等，揭示WC-Co硬质合金表面纳米碳粒子的析出和自润滑机制，实现减磨功能优化。本研究对发展WC金属化合物高温非平衡相变理论，开发新型WC-Co硬质合金表面改性技术具有重要的指导意义。

中文关键词： 强流脉冲电子束；WC-Co硬质合金；表面改性；纳米碳粒子；自润滑

英文摘要： With the rapid development of modern processing and manufacturing industries, there is an increasing demand for WC-Co hard alloy with good performance. The low surface hardness and poor wear resistance constitute the inadequate factors of current hard alloy tools made of WC grains larger than 0.3μm.The service properties of WC-Co hard alloy can be improved effectively by using high energetic beam surface modification, where does not exist the consideration of adhesion strength inherent in the coating technologies. However, the surface modification techniques with high energetic beams have been limited greatly due to the requirement of complicate and costly equipments. In the previous work, the surface modification of WC-Co hard alloy was carried out with a self-made high current pulsed electron beam (HCPEB) device designed by the applicant. The in-situ precipitation of dispersed nano carbon partilcles (NCPs) from WC grains was discovered in the surface modified layer, and this phenomenon brought a great improvement in the wear resistance of more than ten times.Up to now,the formation mechanism of NCPs and its effect on the wear property of WC-Co hard alloy remain unclear. Therefore, the behavior of NCPs precipitation induced by HCPEB surface modification and its influence on the tribological properties of WC-Co hard alloy will be investigated systematically in the present project, including the precipitation threshold and microstructure evolution of NCPs, the structure transformation and movement of NCPs during friction and wear processes, etc. Basing on the experimental and theoretical analyses, the precipitaion mechanism and self-lubrication function of NCPs in the surface layer of WC-Co hard alloy induced by HCPEB surface modification will be revealed together with the optimum treating parameters accordingly. This work will be of important significance to the theories of high-temperature, non-equilibrium phase transformation of WC intermetallic compound and also the exploration of effective methods for WC-Co hard alloy surface modification.

英文关键词： high current pulsed electron beam;WC-Co hard alloy;surface modification;nano carbon particle;self-lubricating