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http://hdl.handle.net/10773/19490
Title: | Mechanical behaviour of zirconia-mullite directionally solidified eutectics |
Author: | Carvalho, R. G. Oliveira, F. J. Silva, R. F. Costa, F. M. |
Keywords: | CERAMIC COMPOSITES MICROSTRUCTURE FIBERS SYSTEM TEMPERATURE WHISKER SINGLE ALLOY |
Issue Date: | 2014 |
Publisher: | ELSEVIER SCI LTD |
Abstract: | Laser floating zone technique (LFZ) is used to grow directionally solidified eutectic (DSE) zirconia-mullite composite fibres (30:70 in wt.%). A notable increase in hardness is observed from 11.3 to 21.2 GPa as the pulling rate increases from 10 to 500 mm/h, due to the ultra-fine eutectics developed at very high growth rates. The indentation fracture toughness reaches a maximum value of 3.5 MPa m(1/2) for the fibre pulled at 100 mm/h, almost three times the value of 1.2 MPa m(1/2) determined for LFZ single-crystal mullite. The eutectic dendrites that develop along the growth direction are immersed in a glassy phase whose brittleness is counteracted by the beneficial ultra-fine morphology, giving a bending strength maximum of 534 MPa. Yet, the soft nature of the glassy matrix prevails at the high temperature testing (1400 degrees C), causing a decrease to about one-half of the RT value in the fibres with less glassy phase content. (C) 2014 Elsevier Ltd. All rights reserved. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/19490 |
DOI: | 10.1016/j.matdes.2014.04.050 |
ISSN: | 0261-3069 |
Publisher Version: | 10.1016/j.matdes.2014.04.050 |
Appears in Collections: | CICECO - Artigos |
Files in This Item:
File | Description | Size | Format | |
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Mechanical behaviour of zirconia-mullite directionally solidified eutectics_10.1016j.matdes.2014.04.050.pdf | 1.43 MB | Adobe PDF |
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