| Autor: |
Chun, C. H., Polonis, D. H. |
| Zdroj: |
Journal of Materials Science; January 1993, Vol. 28 Issue: 15 p4134-4142, 9p |
| Abstrakt: |
The temperature coefficient of electrical resistivity (TCR) of the commercial Ti-15-3 alloy is negative, if the alloy is in the 100% ß condition. The TCR increases from negative to positive values as a result of precipitation of the ? and a phases during ageing. An incubation or transient period, during which the value of TCR remains essentially unchanged, precedes the formation of the ? phase; this transient period decreases with increasing ageing temperature over the range 250–400 °C. Changes in the value of TCR signal the initiation of beta decomposition before the ? phase can be detected by conventional TEM and diffraction techniques. Reversion of the ? phase by up-quenching after ageing restores the original negative value of TCR. If both a and ? phases are present in the aged condition, only partial recovery of the quenched TCR value is possible, indicating that the alpha phase is not reverted by up-quenching. The results point to the potential value of TCR determinations for monitoring the initiation of ß decomposition in titanium alloys exposed to temperatures above room temperature. |
| Databáze: |
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| Externí odkaz: |
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