Indentation size effect in 2nd and 3rd generation advanced intermetallic TiAl alloys: theoretical and experimental estimation of dislocation density.
Saved in:
| Title: | Indentation size effect in 2nd and 3rd generation advanced intermetallic TiAl alloys: theoretical and experimental estimation of dislocation density. |
|---|---|
| Authors: | Nath, Prekshya1 (AUTHOR), Bhattacharjee, Amit2 (AUTHOR), Sen, Indrani1 (AUTHOR) indrani.sen@metal.iitkgp.ac.in |
| Source: | Journal of Materials Science. Feb2024, Vol. 59 Issue 7, p3066-3086. 21p. |
| Subjects: | Dislocation density, Dislocation nucleation, Heterogenous nucleation, Aerospace industries, Automobile industry, Nanoindentation |
| Abstract: | The present study focuses on characterizing the mechanical properties of as-cast and heat-treated 2nd and 3rd generation intermetallic TiAl alloys, which is of practical importance considering its application in the aerospace and automobile industries. Assessing the small-scale properties is crucial for such applications. Indentation size effect (ISE) for TiAl alloys is thoroughly examined using the instrumented nanoindentation technique. It is noted that ISE of TiAl alloys is significantly influenced by the composition, microstructure, and prior deformation characteristics of the system. Prominent ISE is noted for the 3rd generation alloys, as compared to the 2nd generation ones. Theoretical estimations show hardness as a function of geometrically necessary dislocations (GNDs) and statistically stored dislocations. The distribution of GNDs beneath the indentation volume is also experimentally validated. The pre-strained alloys show a lesser extent of ISE and higher bulk hardness owing to the occurrence of preexisting dislocations and twins. The initiation of plasticity at the nanoscale is also dictated by the inherent dislocation characteristics of the alloys. Lower pop-in loads are noticed for pre-strained alloys that are related to the heterogeneous nucleation of dislocations. Overall, this comprehensive study on ISE establishes a correlation between microscopic and bulk hardness and further unravels the distinctive deformation mechanism, active at different length scales from nano to bulk region. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Materials Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. 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.) | |
| Database: | Engineering Source |
|
Full text is not displayed to guests.
Login for full access.
|
|
| Abstract: | The present study focuses on characterizing the mechanical properties of as-cast and heat-treated 2nd and 3rd generation intermetallic TiAl alloys, which is of practical importance considering its application in the aerospace and automobile industries. Assessing the small-scale properties is crucial for such applications. Indentation size effect (ISE) for TiAl alloys is thoroughly examined using the instrumented nanoindentation technique. It is noted that ISE of TiAl alloys is significantly influenced by the composition, microstructure, and prior deformation characteristics of the system. Prominent ISE is noted for the 3rd generation alloys, as compared to the 2nd generation ones. Theoretical estimations show hardness as a function of geometrically necessary dislocations (GNDs) and statistically stored dislocations. The distribution of GNDs beneath the indentation volume is also experimentally validated. The pre-strained alloys show a lesser extent of ISE and higher bulk hardness owing to the occurrence of preexisting dislocations and twins. The initiation of plasticity at the nanoscale is also dictated by the inherent dislocation characteristics of the alloys. Lower pop-in loads are noticed for pre-strained alloys that are related to the heterogeneous nucleation of dislocations. Overall, this comprehensive study on ISE establishes a correlation between microscopic and bulk hardness and further unravels the distinctive deformation mechanism, active at different length scales from nano to bulk region. [ABSTRACT FROM AUTHOR] |
|---|---|
| ISSN: | 00222461 |
| DOI: | 10.1007/s10853-023-09320-7 |
