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case1057156303.pdf (10.4 MB)
ETD Abstract Container
Abstract Header
The martensitic transformation in zirconia
Author Info
Behrens, Gesa
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=case1057156303
Abstract Details
Year and Degree
1993, Doctor of Philosophy, Case Western Reserve University, Materials Science and Engineering.
Abstract
The metastable t-ZrO
2
particles in both Y-TZP and Mg-PSZ can transform to m-ZrO
2
, and in the PSZ also to o-ZrO
2
, via a martensitic transformation. This research has demonstrated that the transformation is controlled by the thermally activated, stress-assisted nucleation of the martensite phase. The thermally activated character of the phase change was manifested as isothermal transformation kinetics in both materials: Residually stressed regions in indented Y-TZP's underwent isothermal t ⇒ m transformation during post-indentation anneals up to ~500°C. In Mg-PSZ's, slow isothermal t ⇒ m and t ⇒ o transformations occurred at room temperature after a short anneal at 1000°C, which reverses the room temperature aging. The phase transitions were accompanied by substantial transformation plasticity: Forward and reverse transformations during anneals in the residually stressed regions in the TZP caused large volume and shape changes, whose simulation with a finite element model was partially successful. In Mg-PSZ's the transformation was induced by internal stresses during room temperature aging as well as by external stresses applied during stress-relaxation tests; again, ample transformation plasticity ensued. Furthermore, the effect of the indentation-induced transformation in Mg-PSZ on the growth of indent cracks during four-point bending was investigated, and the crystallographically oriented and autocatalytic deformation zones around indents in Y-PSZ single crystals were analyzed.
Committee
Arthur Heuer (Advisor)
Pages
307 p.
Subject Headings
Engineering, Materials Science
Keywords
martensitic transformation
;
zirconia
Recommended Citations
Refworks
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RIS
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Citations
Behrens, G. (1993).
The martensitic transformation in zirconia
[Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1057156303
APA Style (7th edition)
Behrens, Gesa.
The martensitic transformation in zirconia.
1993. Case Western Reserve University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=case1057156303.
MLA Style (8th edition)
Behrens, Gesa. "The martensitic transformation in zirconia." Doctoral dissertation, Case Western Reserve University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1057156303
Chicago Manual of Style (17th edition)
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Document number:
case1057156303
Download Count:
1,205
Copyright Info
© 1993, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.