Collaborative Research: Tailoring the Stability and Deformation of Nanocrystalline Alloys through Hierarchical Engineering

非技术描述：纳米晶金属正迅速被认为是一种新型的工程材料，具有高强度和高耐磨性等优越的机械性能。尽管这些材料具有巨大的潜力，但结构的不稳定性和有限的延展性继续阻碍着它们的最佳技术用途。本研究将计算材料科学和实验材料科学相结合，探索了一种通过在晶体基质材料中引入周期性非晶区来改善纳米晶金属稳定性和力学行为的新方法。通过了解这些合金的稳定性和机械性质，这一活动有助于开发具有可调性能的新一代结构材料。概述的框架还为看似不同的科学学科开发了协作环境，并刺激了现代冶金领域的新研究领域。在本科工程实验室课程中增加新的教育模块，将综合计算材料工程的原理注入石溪大学和德雷克塞尔大学现有的工程课程中。高中生通过合作研究项目参与研究，这需要有重点的计算和实验组件，并在互动研究或“iResearch”研讨会上向工程实验室注册的本科生展示结果。这些努力丰富了高中生和大学生的研究机会，促进了学生在STEM学科中的留存，并展示了工程研究如何对社会产生积极影响。技术描述：这项研究的目标是对纳米级晶界物理和更大结构长度尺度上的界面之间的相互作用有一个新的基本理解，这些界面是通过将周期性的非晶区引入到单片纳米晶体结构中而产生的。该项目将大规模并行原子模拟与由溶质稳定的纳米晶界和周期性分布的非晶层组成的纳米结构合金的设计、合成和机械测试相结合。这项研究正在研究这种复合结构如何影响纳米晶晶界网络的稳定性，并增强速率限制变形物理，以提高延性。学生们正在接受尖端原位表征方法、纳米机械测试和计算建模方面的培训，以建立微观结构变量与其热稳定性、变形机制分布和测量的机械性能之间的关联。通过发展这种相关性，这项研究正在推进对新材料结构的基本理解，以提高纳米晶金属的延展性，并有可能改变目前对稳定合金纳米结构设计的观点。

NON-TECHNICAL DESCRIPTION: Nanocrystalline metals are rapidly becoming regarded as a new class of engineering materials with advantageous mechanical properties, such as high strength and increased wear resistance. Despite the tremendous potential of these materials, structural instabilities and limited ductility continue to hinder their best technological utility. This research combines computational and experimental materials science to investigate a novel approach for improving the stability and mechanical behavior of nanocrystalline metals by introducing periodic non-crystalline regions into the crystalline matrix material. By understanding the stability and mechanical nature of these alloys, this activity assists in the development of a new generation of novel structural materials with tunable properties. The outlined framework also develops collaborative environments for seemingly disparate scientific disciplines and stimulates new research areas in the field of modern metallurgy. The addition of new educational modules into undergraduate engineering laboratory courses is infusing principles of integrated computational materials engineering into the existing engineering curricula at both Stony Brook and Drexel University. High school students are engaging in the research through cooperative research projects, which requires focused computational and experimental components, and presentation of the results at Interactive Research or "IResearch" workshops to undergraduates enrolled in the engineering laboratories. These endeavors are enriching research opportunities for students at the high school and collegiate levels, promoting student retention in STEM disciplines, and demonstrating how engineering research can positively impact society.TECHNICAL DESCRIPTION: The objective of this research is to develop a new fundamental understanding of the interplay between nanoscale grain boundary physics and interfaces at larger structural length scales, which are generated by introducing periodic amorphous regions into the monolithic nanocrystalline structure. This project combines massively-parallel atomistic simulations with the design, synthesis, and mechanical testing of nanostructured alloys composed of solute-stabilized nanoscale grain boundaries and periodically distributed amorphous layers. The research is examining how such composite structures influence stability of the nanocrystalline grain boundary network and augment the rate limiting deformation physics for enhancing ductility. Students are being trained in cutting-edge in situ characterization methods, nanomechanical testing, and computational modeling to establish correlations between microstructural variables and their thermal stability, deformation mechanism distributions, and measured mechanical properties. By developing such correlations, this research is advancing the fundamental understanding of new material architectures for enhancing ductility in nanocrystalline metals with the potential to transform current perspectives on the design of stable alloy nanostructures.