NIRT: Mechanical Behavior of Bulk Nanostructured Materials

University Of California-Irvine, Irvine CA

Investigators

Abstract

This grant is on a study of the mechanical properties of bulk nanocrystalline materials produced using different techniques such as cryomilling, severe plastic deformation and electrodeposition. A major objective is to elucidate and understand the mechanical properties of nc-materials, particularly including their strength, ductility, creep, superplasticity, and fatigue. Pure metals with different crystal structures (FCC, BCC and HCP) will be considered along with superplastic Zn-22%Al eutectoid as well as commercial alloys such as Inconel and ultra-fine grained structural steel. The goal is to use novel indentation technique in-situ in electron microscope along with tensile, shear and fatigue tests on bulk nanocrystalline samples. Along with the experimental studies, computational models based on atomistic simulations will be developed to predict the mechanical response and to correlate with the experimental results. The focus of the research on mechanical behavior of nc-materials is on their potentially high strength, the possibility of enhanced creep rates at moderate to low temperatures by grain boundary diffusion, the possibility that these materials may permit superplastic forming at exceptionally high rates or low temperatures, and their response under cyclic loading. The possible applications for chemical, mechanical and electromagnetic technologies will be explored. In addition to providing improved understanding of mechanical behavior in nanocrystalline materials, with implications for how they can be exploited in engineering applications, the program will provide graduate and undergraduate students with useful educational experiences that will contribute to their training, skills, knowledge, and professional careers. Five investigators at three different academic institutions coordinate the research program with plans to establish collaborations with national laboratories such as Los Alamos National Laboratory and Lawrence Livermore National Laboratory.