Theoretical and Experimental Investigations of Gum Metal

胶质金属的理论与实验研究

• 批准号: 0706554
• 负责人: Daryl Chrzan
• 金额: $ 40.5万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-15 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0706554&HistoricalAwards=false
• 关键词: Theoretical; Experimental; Investigations; Gum; Metal

TECHNICAL: PIs will pursue a transformative research program to study in detail the mechanical properties of the recently discovered class of Ti-Nb alloys known as Gum Metals. Gum Metals display super-elasticity, high strength, and significant ductility all in the absence of traditional, dislocation mediated plasticity. In an effort previously funded (in part) through an NSF NIRT, PIs have conducted a rudimentary analysis of the mechanical properties of these materials. Specifically, PIs have demonstrated that Gum Metals are deforming near their ideal strength limit. Further, PIs demonstrated that the dislocations may be pinned easily, even at stresses approaching the ideal strength. Using nanoindentation experiments, PIs showed that the material deforms through (apparently) continuous rotations of nanoscale volume elements. All of these properties have been linked to an electron-filling-induced transition from a body-centered cubic to a hexagonal close packed structure. PIs will expand substantially their prior investigations of Gum Metal behavior in two directions. First, PIs will develop a more detailed understanding of the mechanical properties of Gum Metals. These studies will expand to include the study of dislocation cores, as well as more detailed mapping of the nanoscale deformation patterns associated with nanoindentation. PIs will use theory to identify new alloys that are candidates for Gum Metal behavior. PIs will synthesize the alloys in thin film form and explore directly their mechanical properties. NON-TECHNICAL: Gum Metal behavior presents several exciting opportunities for materials theorists and metallurgists. Since the mechanical properties of these materials are linked to quantities that can be computed directly using the best available quantum mechanical based total energy methods, there is a genuine opportunity for rapid, computer aided, advanced engineering of these alloys. Further, theory will be used to identify other candidates for Gum Metal behavior. PIs' work is aimed at exploiting these opportunities, and it will advance the understanding of Gum Metal behavior and, more generally, an understanding of metallurgical possibilities. The project will have a broad impact in a number of ways. First, there will be two graduate students working directly on the project, and their research conducted within this program will advance their Ph.D. studies. Each student will be encouraged to write papers and to attend meetings of professional societies in order to disseminate their research results. Second, the research results will be incorporated directly into the graduate level Computational Materials Science course taught at Berkeley. Third, the PIs will recruit undergraduates to work on the project using programs at Berkeley aimed at engaging students from underrepresented groups in research. Within a much broader perspective, the existence of alloys with mechanical properties that conflict with 80 years of metallurgical wisdom is truly exciting. The potential for the engineering of advanced materials is clear. The research program may lead to a broad new class of alloys with "super" properties and numerous technological applications.

技术：PI 将开展一项变革性研究计划，详细研究最近发现的一类 Ti-Nb 合金（称为橡胶金属）的机械性能。橡胶金属在缺乏传统的位错介导的塑性的情况下表现出超弹性、高强度和显着的延展性。在之前由 NSF NIRT 资助（部分）的一项工作中，PI 对这些材料的机械性能进行了初步分析。具体而言，PI 已证明橡胶金属的变形接近其理想强度极限。此外，PI 表明，即使在接近理想强度的应力下，位错也可以轻松固定。通过纳米压痕实验，PI 表明材料通过纳米级体积元素（显然）的连续旋转而变形。所有这些特性都与电子填充引起的从体心立方到六方密堆积结构的转变有关。 PI 将在两个方向上大幅扩展他们之前对橡胶金属行为的研究。首先，PI 将对橡胶金属的机械性能有更详细的了解。这些研究将扩展到包括位错核心的研究，以及与纳米压痕相关的纳米级变形模式的更详细的映射。 PI 将利用理论来识别适合橡胶金属行为的新合金。 PI 将合成薄膜形式的合金并直接探索其机械性能。非技术性：橡胶金属的行为为材料理论家和冶金学家提供了一些令人兴奋的机会。由于这些材料的机械性能与可以使用基于量子力学的最佳可用总能量方法直接计算的量相关，因此对于这些合金的快速、计算机辅助、先进工程有真正的机会。此外，理论将用于识别橡胶金属行为的其他候选者。 PI 的工作旨在利用这些机会，它将增进对橡胶金属行为的理解，更广泛地说，增进对冶金可能性的理解。该项目将在多个方面产生广泛的影响。首先，将有两名研究生直接从事该项目，他们在该项目内进行的研究将推动他们的博士学位。研究。我们将鼓励每个学生撰写论文并参加专业协会的会议，以传播他们的研究成果。其次，研究成果将直接纳入伯克利分校教授的研究生计算材料科学课程。第三，PI 将利用伯克利分校的项目招募本科生参与该项目，旨在让代表性不足群体的学生参与研究。从更广阔的角度来看，合金的机械性能与 80 年来的冶金智慧相冲突的存在确实令人兴奋。先进材料工程的潜力是显而易见的。该研究计划可能会产生一类具有“超级”性能和众多技术应用的新型合金。