{l_angle}111{r_angle} Slip in NiAl single crystals between 4.2K and 100K
- Univ. of Oxford (United Kingdom). Dept. of Materials
- GE Aircraft Engines, Cincinnati, OH (United States). Engineering Materials Technology Labs.
- UES Inc., Dayton, OH (United States). Materials Research Division
Slip in {l_angle}111{r_angle} directions is a deformation mode found in many intermetallic compounds ordered into the B2 (CsCl) structure, but in NiAl it is active only under the limiting conditions of uniaxial loading along {l_angle}100{r_angle} and low testing temperatures. This paper investigates the deformation characteristics of {l_angle}100{r_angle} oriented NiAl tested between 4.2K and 300K. Compression tests have shown that below about 100 K, deformation takes place by slip in {l_angle}111{r_angle} directions without kinking, whereas between 100K and 300K kinking in the form of shearing on {l_brace}100{r_brace} becomes the dominant mode of plastic deformation, occurring usually near one or both ends of the compression samples. The yield stress has been found to exhibit a normal decrease with temperature, but at a rate that is smaller than most bcc metals. The sensitivity of the flow stress to strain-rate changes is also characteristically small, giving activation volumes around b{sup 3}, b being the Burgers vector of a{l_angle}111{r_angle} superdislocation. Both slip line observations and transmission electron microscopy have shown slip mainly on {l_brace}110{r_brace} near 80K, but with increasing activity on {l_brace}112{r_brace} and cross-slip between {l_brace}110{r_brace} and {l_brace}112{r_brace} with the lowering of temperature to 4.2K.
- OSTI ID:
- 78330
- Report Number(s):
- CONF-941144--; ISBN 1-55899-265-0
- Country of Publication:
- United States
- Language:
- English
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