Abstract
Compression tests between 1250 and 1550 degrees C and 10(-5) and 5 x 10(-3) s(-1) and transmission electron microscopy have been employed to investigate the high temperature mechanical properties and the deformation mechanisms of the C15 Cr2Nb Laves phase. The stress-peaks in the compression curves during yielding were explained using a mechanism similar to strain aging combined with a low initial density of mobile dislocations. The primary deformation mechanism is slip by extended dislocations with Burgers vector 1/2 <110 >, whereas twinning is more frequent at 10(-4) s(-1). Schmid factor analysis indicated that twinning is more probable in grains oriented so as to have two co-planar twinning systems with high and comparable resolved shear stresses. Twinning produced very anisotropic microstructures. This may be due to synchroshear: a self-pinning mechanism which requires co-operative motion of zonal dislocations. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Original language | English |
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Pages (from-to) | 1873-1884 |
Number of pages | 12 |
Journal | Acta Materialia |
Volume | 55 |
Issue number | 6 |
DOIs | |
Publication status | Published - 1 Apr 2007 |
Keywords
- transmission electron microscopy (TEM)
- high temperature deformation
- mechanical properties testing
- laves phases
- compression test