In situ straining experiments on Fe{sub 70}Al{sub 30} single crystals
- CEMES/CNRS, Toulouse (France)
- Inst. fuer Metallforschung, Muenster (Germany)
Fe{sub 703}Al single crystals have been investigated in situ below and in the temperature range of the yield stress anomaly (300K and 573K respectively) in which the structure is D0{sub 3}. The dislocations involved are imperfect (a{sub o}/2{l_angle}111{r_angle}Burgers vector) due to the stress level and the Al-hyperstoichiometry. They have a dominant screw character which can be explained by the core spreading of each partial dislocations. Thus the motion of the dislocations is controlled by a Peierls-type mechanism. They glide in {l_brace}110{r_brace} planes but cross slip and bending of screw segments onto {l_brace}112{r_brace} are frequent. Further cross slip back onto the {l_brace}110{r_brace} glide plane leads to the formation of many dipoles and debris. Below T{sub a}, dislocations move individually whereas in the temperature range of the anomaly, they propagate collectively by bursts creating microscopic instabilities. The yield stress anomaly is thought to be in particular related to dynamic strain aging may be due to relaxation of the APB ribbon connecting the two partials.
- OSTI ID:
- 78309
- Report Number(s):
- CONF-941144--; ISBN 1-55899-265-0
- Country of Publication:
- United States
- Language:
- English
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