Project Details
Projekt
FOR 714: Plasticity in Nanocrystalline Metals and Alloys
Subject Area
Materials Science and Engineering
Term
from 2006 to 2012
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 19964558
Metals with a grain size around 30 nm and below exhibit unique mechanical properties with significant potential for application. This results from the modified or even entirely new mechanisms which carry the deformation at such small grain size. Presently we dispose of only a rudimentary understanding of these mechanisms. Yet, their investigation has become the subject of intense scientific interest. In this context, the activities within the Research Unit span the areas of synthesis, characterisation, and modelling. We aim to elucidate the following issues:
(1) Which deformation mechanisms dominate in a material of given grain size, alloy composition, and stacking fault energy, subject to given conditions of deformation, such as temperature, strain rate, or state of stress?
(2) What are the resulting constitutive laws?
(3) Which strategies for tailoring the microstructure and the composition lead to materials with optimum properties in relation to processing and mechanical performance? Internationally there are intense research efforts devoted to mechanical properties of nanomaterials, with emphasis in the fields of ultrafine grained materials, amorphous/crystalline nanocomposites, and thin films. The focus of the present research project is on an as yet incompletely investigated class of materials at the lower end of the grain-size scale, namely single-phase nanocrystalline bulk materials with a grain size around 30 nm and below. Besides elementary metals we investigate - as a novel aspect - nanocrystalline solid solutions. Emphasis is on applying different deformation and characterisation methods to samples, prepared by the same synthesis techniques and with closely comparable microstructure. In this way, we intend to achieve consistency and comparability between experiments, in particular with respect to the various aspects of the microstructure. This will enable a meaningful comparison of the results from a wide range of experiments. A focus concerns in-situ methods, including x-ray diffraction with synchrotron radiation and transmission, as well as scanning electron microscopy.
(1) Which deformation mechanisms dominate in a material of given grain size, alloy composition, and stacking fault energy, subject to given conditions of deformation, such as temperature, strain rate, or state of stress?
(2) What are the resulting constitutive laws?
(3) Which strategies for tailoring the microstructure and the composition lead to materials with optimum properties in relation to processing and mechanical performance? Internationally there are intense research efforts devoted to mechanical properties of nanomaterials, with emphasis in the fields of ultrafine grained materials, amorphous/crystalline nanocomposites, and thin films. The focus of the present research project is on an as yet incompletely investigated class of materials at the lower end of the grain-size scale, namely single-phase nanocrystalline bulk materials with a grain size around 30 nm and below. Besides elementary metals we investigate - as a novel aspect - nanocrystalline solid solutions. Emphasis is on applying different deformation and characterisation methods to samples, prepared by the same synthesis techniques and with closely comparable microstructure. In this way, we intend to achieve consistency and comparability between experiments, in particular with respect to the various aspects of the microstructure. This will enable a meaningful comparison of the results from a wide range of experiments. A focus concerns in-situ methods, including x-ray diffraction with synchrotron radiation and transmission, as well as scanning electron microscopy.
DFG Programme
Research Units
Projects
- Aufklärung von Verformungsmechanismen mittels Synchrotron-Röntgenstrahlung und elektronenmikroskopischen Methoden (Applicants Gruber, Patric Alfons ; Hahn, Horst ; Kübel, Christian )
- Gefüge, Defektstruktur und Diffusion (Applicants Weißmüller, Jörg ; Wilde, Gerhard )
- Koordinierungsaufgaben (Applicant Kraft, Oliver )
- Micro- and Macromechanical Properties of Fully Densified Nanocrystalline Metals (Applicants Fecht, Hans-Jörg ; Ivanisenko, Julia )
- Modellierung, Computersimulation, Mechanismen der Verformung nanokristalliner Metalle (Applicants Albe, Karsten ; Gumbsch, Peter )
- Untersuchung der plastischen Verformung nanokristalliner Metalle unter verschiedenen Spannungszuständen mit hoch ortsauflösenden und makroskopisch mittelnden Prüfverfahren. (Applicants Birringer, Rainer ; Kraft, Oliver )
Spokesperson
Professor Dr.-Ing. Jörg Weißmüller
Deputy
Professor Dr. Oliver Kraft
