Measurement of the effective activation volume in 45XD titanium aluminides by repeated transient tests
✍ Scribed by Frédéric Diologent; Tomas Kruml
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 751 KB
- Volume
- 487
- Category
- Article
- ISSN
- 0921-5093
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✦ Synopsis
The mechanical behavior of Ti-45Al-2Mn-2Nb (at.%) containing 0.8 vol.% TiB 2 was studied from room temperature up to 1090 K. The alloy shows a slight anomalous increase of flow stress with temperature around 700 K, which is rarely encountered in two-phase ␥/␣ 2 TiAl. The technique of repeated stress relaxations allows the determination of the apparent and effective activation volumes along the stress-strain curve up to 900 K. The activation volume shows two important features: (i) large variations with strain at room temperature and (ii) a sharp increase with temperature in the stress anomaly domain, indicating the existence of two different dislocation mechanisms operating, respectively, below and above the flow stress anomaly.