FRG: M_n+1AX_n Phase Solid Solutions: Unique Opportunities at Engineering Bulk and Surface Properties

FRG：M_n 1AX_n 相固溶体：工程体积和表面性能的独特机会

• 批准号: 0503711
• 负责人: Michel Barsoum
• 金额: --
• 依托单位: Drexel University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0503711&HistoricalAwards=false
• 关键词: FRG; M_n+1AX_n; Phase; Solid; Solutions

NON-TECHNICAL DESCRIPTION: The properties of an emerging family of inorganic, nano-laminate engineered compounds will be investigated by a focused research group (FRG) of investigators from Drexel and Rowan Universities. These materials with the general formula Mn+1AXn (where n = 1 to 3, M is an early transition metal, A is an A-group (mostly IIIA and IVA) element and X is either C and/or N) and their solid solution alloys known as the so-called MAX phases feature unique chemical, physical, electronic and mechanical properties. They possess superb machinability and extremely low friction coefficients despite being extremely stiff materials. This combination of properties bridges some of the outstanding properties of metals and ceramics within one class of material, the MAX phases. These properties make MAX phases an ideal choice in many areas, for example those requiring low-wear, high-temperature application in aerospace, electronics, tools and consumer goods. The efforts in this program encompass a broad range of experimental and theoretical simulation tools and resources for the characterization, modeling, prediction and manipulation of properties. This program represents a partnership of Drexel, a Ph.D.-granting university, with Rowan, a four-year undergraduate university with a strong tradition of undergraduate research excellence. The linking of students, faculty and resources from both institutions will bring undergraduates and graduate students together in an interdisciplinary environment to provide broader educational and research experiences, to develop important analytical skills, to reinforce their knowledge of the materials through direct interactions, and to further stimulate interest among actively participating and talented undergraduates to pursue graduate studies in a science and engineering discipline.TECHNICAL DETAILS: The MAX phases are among the few polycrystalline solids that deform by a combination of kink and shear band formation, together with delaminations within individual grains. The unusual combination of properties is traceable to their layered structure, the metallic-covalent nature of the MX bonds that are exceptionally strong, together with M-A bonds that are relatively weak, especially in shear. While the potential of select Mn+1AXn phases for high temperature structural applications is beginning to be realized, little is understood about how their thermal, electronic and mechanical properties can be effectively tuned to produce new and unexpected combination of properties in their solid solutions. Herein we propose to explore new materials using combinatorial materials synthesis along with first-principles calculations of electronic properties and lattice dynamical calculations of MAX-phase solid solutions. With bulk and thin-film analytic experimental techniques that have proven to be successful in characterizing these phases, efficient coverage of the compositional and synthetic processing parameter space will enable rapid identification of solid solutions with attractive, and quite possibly novel, combinations of properties. Characterization will include nano-tribological measurements such as local friction and surface energy dissipation via variable temperature scanning probe microscopy; local stress-strain analysis via nanoindentation; linkage of lattice dynamics with mechanical properties via in situ Raman scattering; and probing of electronic, optical and magnetic properties in bulk and thin films.

非技术描述：一个新兴的无机纳米层压工程化合物家族的特性将由来自德雷克塞尔大学和罗文大学的研究人员组成的重点研究小组（FRG）进行研究。 这些具有通式Mn+1AXn（其中n = 1至3，M是前过渡金属，A是A族（主要是IIIA和IVA）元素，X是C和/或N）的材料和它们的固溶体合金（称为所谓的MAX相）具有独特的化学、物理、电子和机械性能。 它们具有极好的机械加工性和极低的摩擦系数，尽管是非常坚硬的材料。 这种性能组合将金属和陶瓷的一些出色性能结合在一起，形成了一类材料，即MAX相。这些特性使MAX相成为许多领域的理想选择，例如航空航天、电子、工具和消费品中需要低磨损、高温应用的领域。该计划的努力包括广泛的实验和理论模拟工具和资源，用于特性的表征，建模，预测和操纵。 这个项目代表了德雷克塞尔的合作伙伴关系，一个博士-授予大学，与罗文，一个四年制本科大学与本科研究卓越的强大传统。 来自两个机构的学生，教师和资源的联系将使本科生和研究生在跨学科的环境中聚集在一起，以提供更广泛的教育和研究经验，发展重要的分析技能，通过直接互动加强他们对材料的了解，并进一步激发积极参与和有才华的本科生在科学和工程领域攻读研究生课程的兴趣MAX相是为数不多的多晶固体中的一种，其通过扭结和剪切带形成的组合以及单个晶粒内的分层而变形。这种不寻常的性质组合可以追溯到它们的层状结构，MX键的金属共价性质非常强，而M-A键相对较弱，特别是在剪切中。虽然选择Mn+1AXn相用于高温结构应用的潜力开始被认识到，但关于如何有效地调节它们的热、电子和机械性能以在它们的固溶体中产生新的和意想不到的性能组合的了解很少。 在这里，我们建议探索新的材料，使用组合材料合成沿着与第一性原理计算的电子性质和晶格动力学计算的MAX相固溶体。 与散装和薄膜分析实验技术，已被证明是成功的，在表征这些阶段，有效覆盖的组成和合成工艺参数空间将使快速识别的固溶体与有吸引力的，很可能是新颖的，组合的属性。表征将包括纳米摩擦学测量，例如通过变温扫描探针显微镜进行的局部摩擦和表面能量耗散;通过纳米压痕进行的局部应力应变分析;通过原位拉曼散射将晶格动力学与机械性能联系起来;以及探测大块和薄膜的电子、光学和磁性。