Development of powder metallurgy route for production of novel fe-al intermetallics for high temperature applications
FeAl based intelmetallic alloys are being proposed as engineering materials for high temperature applications due to their low density, low materials cost, low content of strategic elements and oxidation resistance. These intennetallic alloys are suitable for applications in aggressive and cor...
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| Format: | Thesis |
| Language: | English English English |
| Published: |
2009
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/7317/1/24p%20FAZIMAH%20MAT%20NOOR.pdf http://eprints.uthm.edu.my/7317/2/FAZIMAH%20MAT%20NOOR%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/7317/3/FAZIMAH%20MAT%20NOOR%20WATERMARK.pdf |
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| Summary: | FeAl based intelmetallic alloys are being proposed as engineering materials
for high temperature applications due to their low density, low materials cost, low
content of strategic elements and oxidation resistance. These intennetallic alloys are
suitable for applications in aggressive and corrosive environments up to 900°C.
However they may fail through loss of strength or gradually deteriorate through
reaction with the surrounding atmosphere when exposed to temperature higher than
900°C. Therefore, the fonnation of a stable protective oxide scale or alumina on the
surface is required to protect the underlying materials when exposed to high
temperature. In this research, the FeAl alloys were produced by using powder
metallurgy route which consisted of mechanical alloying process, cold compaction.
sintering, hot compaction and surface treatment via ion implantation. The addition
of reactive elements or their oxides such as Y, Y20 3 and Ce02 by mechanical
alloying or ion implantation method may improve their oxidation resistance through
the enhancement of the alumina scale adhesion to the underlying alloys.
Characterizations by using SEM and XRD were carried out before and after each
process to investigate the microstructure, phase change and fonnation of the oxide
layer. Cyclic oxidation tests were perfonned at 900°C and 11 OO°C to study the
oxidation behavior of these intennetallic alloys. The results showed that the FeAI
intennetallic alloys were successfully produced by mechanical alloying, hot
compaction and surface treatment via ion implantation. The FeAI intennetallic with
3 xl 015 ionlcm2 doses of yttrium implanted exhibited the lowest oxidation kinetics at
900°C while FeAI intennetaIIic with 1 wt% yttria and 9xl 0 15 ionlcm2 doses of
yttrium implanted exhibited the lowest oxidation kinetics at 11 00°c. |
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