微纳尺度类金刚石碳膜动态力学性质及机理研究

Due to their high hardness, high wear resistance and low coefficient of friction, diamond-like coatings (DLC) are widely used in advance machinery, and also showed great potential in micro electromechanical system and aerospace fields. During service the DLC often suffer high strain-rate deformation even impact, and their dynamic behaviour can not be well described by the quasi-static experimental data. In this project, a novel and practical dynamic mechanical testing for thin films will be developed based on an indentation method. The deformation and failure of the DLC will be systematically investigated at different strain rates (10-5~103/s) and impact energy (10-9~10-3J). The dynamic mechanisms during the deformation and fracture for the DLC will be researched intensively with consideration of the thermal stability and their bonding, chemical compositions, thickness, internal stress, the properties of the interface and the substrate,etc. These results can promote the scientific understanding in the deformation mechanisms of DLC and other amorphous materials in a nano/micro scales. Though building appropriate physical models, the corresponding dynamic mechanical properties (dynamic hardness, dynamic toughness, dynamic elastic strain limit and dynamic plastic resistance) for DLC can be determined. Such results can also benefit their engineering applications greatly by evaluating and predicting their reliability and life.

类金刚石碳膜（DLC）具有高硬度、高耐磨性和低摩擦系数，广泛应用于先进工业制造，并在微机械电子系统，航天航空等领域展示出重大应用前景。由于DLC在服役过程中常经受高速形变，甚至冲击载荷，准静态条件下（10-5~10-3s-1）力学性能难以准确评价其动态力学行为。本项目拟基于压入法，发展新型实用化薄膜动态力学实验检测技术与表征方法；系统研究DLC在不同应变速率（10-5~103s-1）和冲击能量（10-9~10-3J）下的形变与失效过程，细化实验动力学参数与薄膜成分与结构、厚度、内应力、界面和基体的交互作用，结合DLC热稳定性研究，明晰其的动力学响应及相关机理，对理解DLC和其他非晶材料在微纳尺度形变失效机理有着重要的科学意义。通过物理模型分析计算DLC动态力学性能（动态硬度，动态韧性，动态弹性应变极限和动态塑性抗力等），对于评价和预测其在实际工况条件下的可靠性和寿命具有重要工程价值。

本项目立足纳米冲击新型实验技术，研究了块体材料和薄膜材料的动态塑性形变与脆性断裂的实验参数作用及数据特征，发展了相关物理分析模型，探究了准静态压入与动态冲击条件下材料内部组织的变化规律；基于纳米多冲实验技术，研究了薄膜材料冲击深度衍生关键参量的统计学特征，探讨了其与薄膜疲劳断裂性能的关联性；从而发展和建立了一系列微纳尺度下材料动态力学性能（动态硬度、动态韧性和疲劳性能）的实验检测技术与表征方法。采用物理气相沉积制备类金刚石碳膜（DLC），厘清了膜厚、沉积时间、沉积偏压及基体等变量对薄膜成分、组织、相组成、力学性能以及摩擦学性能的作用；并且借助纳米冲击的单冲与多冲两类模式，探究了DLC的动态力学性能与疲劳抗力，明晰了其动力学响应及相关机理，对于评价和预测其在实际工况条件下的可靠性和寿命具有重要工程价值。.在完成项目既定内容外，项目执行人开展了多种材料的组织结构-形变失效特征-纳米力学实验方法的关联性研究；结合分子动力学模拟了纳米压入过程，分析了单晶铝内部位错反应机制、单晶硅压入相变及DLC薄膜的压入行为；同时也探究了新型碳材料以及表面技术在新型储能领域的应用；上述相关内容的研究丰富了本项目内涵与外延，对纳米冲击技术与碳基薄膜的理论研究与实际应用有着重要价值。.本项目执行期间负责人以第一作者/通讯作者发表学术论文28篇；项目成员参加国内/国际会议约26人次，其中口头报告10次，墙报2次，参与组办国内会议两次；申请国家发明专利10项；已培养硕士研究生6人。项目负责人获邀在Elsevier出版的专著上撰写纳米力学章节1章，另有7篇论文在准备与投稿中。