Texture of ECAP processed Aluminum
Bozic, Martina (2015)
2015
Master's Degree Programme in Materials Science
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Hyväksymispäivämäärä
2015-02-04
Julkaisun pysyvä osoite on
http://urn.fi/URN:NBN:fi:tty-201501291034
http://urn.fi/URN:NBN:fi:tty-201501291034
Tiivistelmä
In this thesis the studied material was pure aluminum that was processed by Equal Channel Angular Pressing (ECAP). The main research objectives were to determine the texture development of aluminum during ECAP processing, and to study the changes in texture after additional high rate axial compression deformation. Since aluminum is used quite extensively in many industrial applications it is important to get a better understanding of its microstructural changes under different loads; and possibilities that might be gained.
The texture measurements were done using X-ray diffraction (XRD) in parallel beam geometry, and the compression tests were done with Split Hopkinson Pressure Bar device (SHPB) at room temperature. The tested samples were processed by ECAP one, four, and sixteen passes.
The results are presented as pole figures for different lattice planes (111), (200) and (220); and as a 3-dimentional orientation distribution functions (ODF’s). Based on the results, the texture changes significantly depend on how many times the sample is pressed through the ECAP die. Furthermore, the axial compression deformation affects the texture quite dramatically and this change is stronger for the samples with higher number of ECAP passes.
During the work, several practical issues had to be solved and are also included in this paper. The issues were related to the effect of sample preparation and adjustments on the XRD device during the measurements (2θ angle and the defocusing error). The effects of experimental variables are explained in details and their significance is presented and elaborated in the results.
The texture measurements were done using X-ray diffraction (XRD) in parallel beam geometry, and the compression tests were done with Split Hopkinson Pressure Bar device (SHPB) at room temperature. The tested samples were processed by ECAP one, four, and sixteen passes.
The results are presented as pole figures for different lattice planes (111), (200) and (220); and as a 3-dimentional orientation distribution functions (ODF’s). Based on the results, the texture changes significantly depend on how many times the sample is pressed through the ECAP die. Furthermore, the axial compression deformation affects the texture quite dramatically and this change is stronger for the samples with higher number of ECAP passes.
During the work, several practical issues had to be solved and are also included in this paper. The issues were related to the effect of sample preparation and adjustments on the XRD device during the measurements (2θ angle and the defocusing error). The effects of experimental variables are explained in details and their significance is presented and elaborated in the results.