Investigation of pathways for nanoscale high temperature stability via nano-metallic multilayers

University Of Southern California, Los Angeles CA

Investigators

Abstract

NON-TECHNICAL DESCRIPTION: Materials with grain sizes below 100 nm, better known as nanomaterials, provide many exceptional properties. For example, the strength of a material with nanoscale microstructure can be four to five times higher than a larger grain counterpart. However, to fully exploit their performance, the stability of the materials with nanoscale microstructure must be maintained. If grains grow within the microstructure, the extraordinary properties will disappear. This proposal aims to develop a new method to fabricate nanoscale microstructures in such a way that the final material is very stable for a wide range of temperatures. The focus is on understanding how to maintain stability and how to fabricate many different types of metal alloy systems. This research is applicable to nanomaterials used in aerospace, bridges, automotive, and other fields. Additionally, the project has broader impact in the community through education. Specifically, this project launches the "Trojan Panda Program", which brings hands-on science and engineering projects to low-income children in the Los Angeles area. The graduate students involved in the project lead these sessions to expose K-6 students to science and engineering concepts while fostering an interest in STEM fields. TECHNICAL DETAILS: Though nanostructured metallic materials have many attractive properties including high strength, they generally exhibit poor thermal stability which severely limits their application. The complexity of synthesizing metallic nanostructures coupled with convoluted kinetic and thermodynamic phenomena have confined research to a few available systems. To truly exploit nanoscale properties there is a critical need to synthesize and understand the mechanisms that control thermal stability at the nanoscale. This research provides a novel synthesis approach to achieve thermally stable nanocrystalline materials by exploring the microstructural evolution from a multilayered system to an equiaxed nanocrystalline structure. By utilizing nano metallic multilayers (NMMs), this research allows for the synthesis of a wide range of compositions selected from thermodynamic models, while examining intermediate microstructural steps that can elucidate the controlling mechanisms at various temperatures. The graduate students educated in this effort will gain international experience through collaboration with faculty at Ruhr Universität, Bochum in Germany and their Interdisciplinary Center for Advanced Materials Simulations (ICAMS).