Abstract
Neutron scattering is a very efficient method for investigating shape-memory alloys such as Cu-Zn-Al and Cu-Zn. The shape-memory effect is related to a martensitic phase transition, which is not yet fully understood. The two aims of this work are the determination of crystal structure of both phases and finding precursors of the martensitic transition in the parent phase. For a refinement of the crystal structure of the low-temperature phase I investigated first the crystal symmetry, because in most previous work a wrong crystallographic space group was used. Furthermore it was necessary to take stacking faults into account for an exact determination of the structure of the martensite. In the parent phase the degree of order and the temperature factors were determined. In order to investigate precursor effects elastic diffuse and inelastic measurements were performed in the parent phase. The phonon dispersion curves of all symmetry directions for Cu-Zn-Al and some phonon branches in Cu-Zn were measured, but no distinct anomaly was found in contrast to other martensitic phase transitions such as in Ni-Al. The local structure was investigated by elastic diffuse measurements in three dimensions on a Cu-Zn single crystal. The data were analysed considering short-range order and an expansion
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Zolliker, M
[1]
- Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Citation Formats
Zolliker, M.
Neutron scattering on shape-memory alloys Cu-Zn-Al and Cu-Zn; Neutronenstreuung an den Formgedaechtnislegierungen Cu-Zn-Al und Cu-Zn.
Switzerland: N. p.,
1991.
Web.
Zolliker, M.
Neutron scattering on shape-memory alloys Cu-Zn-Al and Cu-Zn; Neutronenstreuung an den Formgedaechtnislegierungen Cu-Zn-Al und Cu-Zn.
Switzerland.
Zolliker, M.
1991.
"Neutron scattering on shape-memory alloys Cu-Zn-Al and Cu-Zn; Neutronenstreuung an den Formgedaechtnislegierungen Cu-Zn-Al und Cu-Zn."
Switzerland.
@misc{etde_10118528,
title = {Neutron scattering on shape-memory alloys Cu-Zn-Al and Cu-Zn; Neutronenstreuung an den Formgedaechtnislegierungen Cu-Zn-Al und Cu-Zn}
author = {Zolliker, M}
abstractNote = {Neutron scattering is a very efficient method for investigating shape-memory alloys such as Cu-Zn-Al and Cu-Zn. The shape-memory effect is related to a martensitic phase transition, which is not yet fully understood. The two aims of this work are the determination of crystal structure of both phases and finding precursors of the martensitic transition in the parent phase. For a refinement of the crystal structure of the low-temperature phase I investigated first the crystal symmetry, because in most previous work a wrong crystallographic space group was used. Furthermore it was necessary to take stacking faults into account for an exact determination of the structure of the martensite. In the parent phase the degree of order and the temperature factors were determined. In order to investigate precursor effects elastic diffuse and inelastic measurements were performed in the parent phase. The phonon dispersion curves of all symmetry directions for Cu-Zn-Al and some phonon branches in Cu-Zn were measured, but no distinct anomaly was found in contrast to other martensitic phase transitions such as in Ni-Al. The local structure was investigated by elastic diffuse measurements in three dimensions on a Cu-Zn single crystal. The data were analysed considering short-range order and an expansion of the static displacements, whereby it became apparent that quadratic terms had to be taken into account, indicating a strong displacement of a few atoms. Both inelastic and elastic diffuse measurements indicate that the <110>-directions are particularly important for the phase transition. (author) figs., tabs., 45 refs.}
place = {Switzerland}
year = {1991}
month = {Oct}
}
title = {Neutron scattering on shape-memory alloys Cu-Zn-Al and Cu-Zn; Neutronenstreuung an den Formgedaechtnislegierungen Cu-Zn-Al und Cu-Zn}
author = {Zolliker, M}
abstractNote = {Neutron scattering is a very efficient method for investigating shape-memory alloys such as Cu-Zn-Al and Cu-Zn. The shape-memory effect is related to a martensitic phase transition, which is not yet fully understood. The two aims of this work are the determination of crystal structure of both phases and finding precursors of the martensitic transition in the parent phase. For a refinement of the crystal structure of the low-temperature phase I investigated first the crystal symmetry, because in most previous work a wrong crystallographic space group was used. Furthermore it was necessary to take stacking faults into account for an exact determination of the structure of the martensite. In the parent phase the degree of order and the temperature factors were determined. In order to investigate precursor effects elastic diffuse and inelastic measurements were performed in the parent phase. The phonon dispersion curves of all symmetry directions for Cu-Zn-Al and some phonon branches in Cu-Zn were measured, but no distinct anomaly was found in contrast to other martensitic phase transitions such as in Ni-Al. The local structure was investigated by elastic diffuse measurements in three dimensions on a Cu-Zn single crystal. The data were analysed considering short-range order and an expansion of the static displacements, whereby it became apparent that quadratic terms had to be taken into account, indicating a strong displacement of a few atoms. Both inelastic and elastic diffuse measurements indicate that the <110>-directions are particularly important for the phase transition. (author) figs., tabs., 45 refs.}
place = {Switzerland}
year = {1991}
month = {Oct}
}