Influence of dislocation mobility on room and high temperature ductility of {l_angle}100{r_angle}-oriented NiAl single crystals
- Univ. of Neuchatel (Switzerland). Inst. of Structural Metallurgy
- General Electric Aircraft Engines, Cincinnati, OH (United States)
The dislocation configurations produced by room and high temperature compression of {l_angle}100{r_angle} oriented single crystals of binary NiAl and in those containing iron and hafnium additions have been analyzed and compared to those obtained by hardness indentation and TEM in situ tensile tests. Kinking occurs during room temperature compression such that {l_angle}100{r_angle} dislocations are activated in all cases but the iron-containing alloy also exhibited a large density of {l_angle}111{r_angle} screw dislocations. The latter however, appear immobile when they are created by hardness indentations of thin foils, while only pile-ups of {l_angle}100{r_angle} segments can propagate. Similarly, although different slip systems are present after high temperature compression, only {l_angle}100{r_angle} dislocation segments have been confirmed to be mobile after room temperature hardness indentation of these predeformed thin foils. The improvement in ductility observed at room temperature in the predeformed specimens of the binary and the iron containing alloys has been attributed to the increased production of these mobile {l_angle}100{r_angle} dislocations.
- OSTI ID:
- 78355
- Report Number(s):
- CONF-941144--; ISBN 1-55899-265-0
- Country of Publication:
- United States
- Language:
- English
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