Materials World Network: Processing-Structure-Property Relationships in Ultra-Fine Grained and Nanostructured Bulk Cu and Cu-Zn Alloys

North Carolina State University, Raleigh NC

Investigators

Abstract

This research is based on collaboration among North Carolina State University (NCSU), the University of Vienna, Austria (UV), and IFW-Dresden, Germany (IFW-D). The scientific objectives of the research are to exploit a range of processing and characterization techniques and expertise to investigate the mechanical behavior of metals and alloys as a function of their grain size and stacking fault energy. In particular, Cu and Cu-Zn alloys are prepared by processing techniques at the various institutions that, when combined, produce artifact-free bulk samples with a grain size range from ultra-fine (< 1000 nm) down to the finest achievable at the nanoscale (~ 10 nm). The combined effort and facilities at NCSU, UV, and IFW-D are needed to achieve the processing objectives. The critical mechanical properties are determined by tensile, shear and nanoindentation tests at NCSU, compression, tensile and torsion tests at IFW-D, and fatigue and fracture toughness at UV. The deformation mechanisms that are operative at the various grain sizes and stacking fault energies are probed by in situ x-ray diffraction line broadening studies under stress at UV and NCSU with collaborators. In situ transmission electron microscopy (TEM) straining studies are done by IFW-D and NCSU, and in situ scanning electron microscopy (SEM) is done at IFW-D. An extensive set of density functional theory (DFT) calculations and large-scale molecular dynamics (MD) simulations are also done at NCSU, while mechanism-based and related modeling is done at NCSU, UV, and IFW-D. The exchange of graduate students and the faculty interactions among NCSU, UV and IFW-D constitute a major part of the project.