Materials World Network: Mechanics and Durability of Diamond-Like Nanocomposites (MADDiLiN): An International Collaboration to Understand Tribo-Mechanical Multiphysical Phenomena

这项工作是宾夕法尼亚大学的研究人员与系统摩擦学和动力学实验室(LTDS；法国里昂)合作进行的，目的是对一类重要的薄膜材料--类金刚石纳米复合材料(DLNS)的摩擦机械功能行为进行物理理解。DLN是完全非晶态的薄膜，由二氧化硅玻璃和氢化无定形碳组成的相互渗透、相互结合的网络组成。即使在恶劣的条件下(高温、高接触应力和超高真空、潮湿和氧化环境)，它们也表现出令人印象深刻的耐用性，这意味着机械(稳定性、强度)和摩擦学(低摩擦和低磨损)性能。该团队追求紧密集成、跨学科、多尺度、多技术的计划，以确定DLN的摩擦机械功能如何取决于本体和表面材料的性能，以及这些性能是如何由结构和组成决定的。由于材料性能的相互依赖，以及执行工作所需的多种技术，这种协作汇集了所需的互补专业知识。将这种综合研究方法应用于具有系统变化组成的DLN薄膜，直接探索其结构-性能-功能行为关系。研究结果有助于设计新的和进一步改进的特定类别的DLN，以及更广泛的非晶态材料。这一点很重要，因为目前在从先进能源系统到制造、航空航天、汽车和信息存储部门的各种应用中，以及在纳米制造和纳米机械设备应用中，类金刚石材料作为涂层的需求很大。非晶态材料普遍存在并有着广泛的应用，因此，需要有新的科学见解来了解它们的组成、结构和材料性质是如何决定它们的功能行为的。从教育的角度来看，这项研究为博士和本科生提供了国际交流经验，使他们在每个地点都获得了独特的和互补的能力。该项目还将把LTD带入宾夕法尼亚大学和桑迪亚国家实验室、美国海军学院和纽约城市大学亨特学院之间正在进行的合作中。

The goal of this effort, a collaboration between researchers the University of Pennsylvania and the Laboratory of Tribology and Dynamics of Systems (LTDS; Lyon, France), is to develop a physically-based understanding of the tribomechanical functional behavior of an important class of thin film materials known as diamond-like nanocomposites (DLNs). DLNs are fully amorphous films consisting of an interpenetrating, interbonded network of silica glass and hydrogenated amorphous carbon. They exhibit impressive durability, meaning mechanical (stability, strength) and tribological (low friction and low wear) performance, even under harsh conditions (elevated temperatures, high contact stresses, and ultrahigh vacuum, humid, and oxidizing environments). The team pursues a closely integrated, interdisciplinary, multi-scale, multi-technique program to determine how the tribo-mechanical functionality of DLNs depends on the bulk and surface material properties, and how these properties are determined by the structure and composition. The collaboration brings together complementary expertise needed because of the interdependency of the material properties, and because of the multiple techniques required to execute the work. The integrated research approach is applied to DLN films with systematically varied compositions to explore the structure-property-functional behavior relationships directly. The outcome of the research can aid in the design of new and further improved classes of DLNs specifically, and amorphous materials more generally. This is important since diamond-like materials are currently in demand for use as coatings in the harsh operating conditions found in applications ranging from advanced energy systems to the manufacturing, aerospace, automotive, and information storage sectors, and also in nanomanufacturing and nanomechanical device applications. Amorphous materials in general are ubiquitous and have broad applications, and so new scientific insights into how their functional behavior is determined by their composition, structure, and material properties is desirable. From an education perspective, this research provides international exchange experiences for Ph.D. as well as for undergraduate students, exposing them to unique and complementary capabilities at each location. The project will also bring LTDS into ongoing collaborations between the University of Pennsylvania and Sandia National Laboratories, the U.S. Naval Academy, and Hunter College-City University of New York.