This research studies individual and combined effects of hydrogen gas exposure
and low temperature on the tribological characteristics of Ti-6Al-4V. Experimental
approaches include test system modification and tribological analysis. An existing ballon-
disk tribometer was modified to allow liquid nitrogen to be constantly injected into
an insulated test chamber to enable testing at low temperature. Twelve 3.8 cm diameter
Ti-6Al-4V disks were manufactured and polished, then half were exposed to pure
hydrogen gas at elevated temperature and pressure and the remaining disks were
untreated. The testing was split in to four groups of three disks based on testing
temperature and previous hydrogen exposure. A silicon nitride ball was used for all tests.
Each group was tested at two normal loads, 10N and 20N, at the same linear speed.
Group 1 was unexposed and tested at room temperature, Group 2 was unexposed and
tested at low temperature, Group 3 was exposed and tested at room temperature and
Group 4 was exposed and tested at low temperature. Average friction coefficients and
the specific wear rate were calculated from the test data. Also high-resolution digital
microscope imaging was used to observe and characterize the wear mechanisms of the four groups of samples. Results show that hydrogen exposure facilitated adhesive wear
of the surface and that low temperature induced a slip-stick wear mechanism under
higher loads, but not at lower loads and regardless of exposure to hydrogen gas. This
research opens avenues for future investigation in effects of hydrogen and low
temperature embrittlement on the tribological performance of materials. With the
increasing interests in hydrogen energy, the present work established a foundation for
future study.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-3193 |
| Date | 15 May 2009 |
| Creators | Gola, Ryan Travis |
| Contributors | Liang, Hong |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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