The effects of microstructural control on the mechanical behavior of Cr{sub 2}Nb-based alloys
- Univ. of Tennessee, Knoxville, TN (United States)
- Oak Ridge National Lab., TN (United States)
Microstructural evaluations and mechanical testing of Laves-phase alloys based on Cr{sub 2}Nb were examined in order to optimize microstructural and mechanical properties by thermomechanical treatment at temperatures up to 1600{degrees}C. At ambient temperatures, single-phase Cr{sub 2}Nb alloys are very hard and brittle due to the complicated crystal structure (C-15). The following results were revealed through examination of the Cr-Cr{sub 2}Nb two-phase region: (a) with increasing amounts of the soft chromium-rich phase, the compression strength and hardness decrease; (b) the annealing treatments studied thus far provided the best break-up of the coarse/brittle Laves-containing eutectic phase in the 94 at.% Cr - 6 at.% Nb (CN-7) alloy; (c) two different anneals, 1 hour at 1600{degrees}C + 4 hours at 1200{degrees}C and 4 hours at 1550{degrees}C + 2 days at 1200{degrees}C, lead to a substantial improvement in the room temperature strength and compressive ductility over previous annealing treatments. Hot Isostatic Pressing has led to only a marginal reduction in casting defects and refinement of the eutectic structure. A combination of hot forging and annealing has been initially promising in refining the brittle eutectic structure.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- OSTI ID:
- 416498
- Report Number(s):
- ORNL/FMP--95/1; CONF-9505204--; ON: DE96001412
- Country of Publication:
- United States
- Language:
- English
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