Title
In-situ neutron diffraction analysis of deformation behavior of ductile rare-earth intermetallic YCu
Degree Type
Dissertation
Date of Award
2009
Degree Name
Doctor of Philosophy
Department
Materials Science and Engineering
First Advisor
Alan M. Russell
Second Advisor
Karl A. Gschneidner
Abstract
Intermetallic compounds exhibit favorable properties for numerous diverse engineering applications. Many intermetallic compounds possess high strength and high stiffness at elevated temperature, excellent corrosion resistance, and low density, making them potentially useful in a wide range of applications. However, several drawbacks, limited ductility in particular, have prevented these compounds from achieving wide-spread application. In order to make full use of potential of intermetallic compounds, these limitations must be better understood and overcome.
In the search for improved ductility in intermetallics, recent findings from an Ames Laboratory research group have uncovered an entire family of compounds possessing the B2 structure which exhibit room temperature tensile ductility. These materials do not require third-element additions, off-stoichiometric chemistry, disordering, or elaborate environmental testing conditions to enhance ductility. Previous studies have investigated various structural and physical properties of this family of compounds, yet the mechanisms for ductility remain uncertain. Low temperature phase transformations are known to occur in several of these compounds. Suggestions for possible mechanisms have included stress-induced phase transformation, as well as the deformation accommodated through crystallographic twinning.
In-situ neutron diffraction allows for observations of structural changes and the relationship to macroscopic physical properties. Using this investigation technique, experiments have been conducted to examine rare-earth intermetallic YCu for evidence of phase transformation, twinning, or indications of other deformation behavior. Results
give insight into the crystal structure of the compound, indicating a high degree of crystal lattice coherency, and resulting dynamical diffraction behavior not commonly observed in engineering materials.
Copyright Owner
Scott H Williams
Copyright Date
2009
Language
en
Date Available
2012-04-30
File Format
application/pdf
File Size
131 pages
Recommended Citation
Williams, Scott H., "In-situ neutron diffraction analysis of deformation behavior of ductile rare-earth intermetallic YCu" (2009). Graduate Theses and Dissertations. 10863.
https://lib.dr.iastate.edu/etd/10863
