التفاصيل البيبلوغرافية
| العنوان: |
Mechanical spectroscopy of a high-Nb-bearing γ -TiAl-based alloy with near-gamma and fully lamellar microstructure. |
| المؤلفون: |
Weller *, M., Clemens, H., Haneczok, G., Dehm, G., Bartels, A., Bystrzanowski, S., Gerling, R., Arzt, E. |
| المصدر: |
Philosophical Magazine Letters; Jun2004, Vol. 84 Issue 6, p383-393, 11p |
| مصطلحات موضوعية: |
SPECTRUM analysis, ALLOYS, MICROSTRUCTURE, ENTHALPY, TEMPERATURE, METALLIC composites |
| مستخلص: |
Intermetallic γ-TiAl sheet material of composition Ti-46 at.%Al-9 at.%Nb and two different microstructures (fine-grained near-gamma and coarse-grained fully lamellar) was studied by mechanical-loss (internal-friction) measurements using two frequency ranges: (I) 0.01-10 Hz and (II) around 2 kHz. The mechanical spectra in range I show (i) a loss peak of Debye type at T ≈ 1000 K, which occurs only in fully lamellar samples; and (ii) a high-temperature damping background above ≈ 1100 K. The values of the activation enthalpy H of the high-temperature background, 4.3 eV (near-gamma) and 4.2 eV (fully lamellar), which were determined from the frequency shift, are distinctly higher than those obtained for TiAl sheet material with low Nb content. The high-temperature damping background is assigned to diffusion-assisted climb of dislocations, and the 1000 K peak ( H = 2.9 eV) to local (reversible) glide of dislocation segments anchored between lamella interfaces. From measurements of the eigenfrequency in range II, the variation of Young's modulus in the temperature range 300-1000 K was determined. [ABSTRACT FROM AUTHOR] |
|
Copyright of Philosophical Magazine Letters is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| قاعدة البيانات: |
Complementary Index |
