Tensile deformation and recovery kinetics of Alloy 690
- Rutgers--the State Univ., Piscataway, NJ (United States). Dept. of Mechanics and Materials Science
The effect of carbon content, grain size and thermal history on the deformation behavior of nickel-base Alloy 690 has been investigated. Carbon content effects the yield strength of Mill Annealed (MA) material, but has no effect in Thermally Treated (TT) material. Also, no effect of carbon content on the workhardening rate was seen in either material. There was an effect of grain size as expected. An interesting aspect of this work showed that TT material consistently has a slightly higher Young's modulus than the MA. As deformation moves into the plastic regime, the TT material displays a two stage hardening process. This consists of a low workhardening rate (n = 0.05), followed by a transition to the more normal workhardening rate (n=0.35). The MA material, on the other hand, does not exhibit the low n region. This unusual deformation behavior is attributable to the presence of planar slip which initiates at the grain boundary over the strain range of 0.2 to 0.7%. These observations are useful to explain the unexpectedly fast strain relaxation behavior seen in this alloy. The recovery kinetics of the alloy have also been studied. Rapid recovery with an activation energy of approximately 5.3 kj/mol occurs when the deformation level is low. This was attributed to a grain boundary self diffusion process. At higher strain levels, recovery is much slower with an activation energy of approximately 14 kJ/mol. This process was attributable to bulk diffusion. Based on TEM and X-ray rocking curve measurements, these results have been explained.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); Rutgers-the State Univ., Piscataway, NJ (United States). Dept. of Mechanics and Materials Science
- Sponsoring Organization:
- EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 7168895
- Report Number(s):
- EPRI-TR-100910; TRN: 92-030750
- Country of Publication:
- United States
- Language:
- English
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36 MATERIALS SCIENCE
NICKEL BASE ALLOYS
TENSILE PROPERTIES
PWR TYPE REACTORS
STEAM GENERATORS
TUBES
CARBON ADDITIONS
COMPUTERIZED SIMULATION
CRACKS
DEFORMATION
GRAIN SIZE
REACTOR MATERIALS
RESIDUAL STRESSES
STRAINS
STRESS ANALYSIS
ALLOYS
BOILERS
CRYSTAL STRUCTURE
ENRICHED URANIUM REACTORS
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
POWER REACTORS
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THERMAL REACTORS
VAPOR GENERATORS
WATER COOLED REACTORS
WATER MODERATED REACTORS
210200* - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
360103 - Metals & Alloys- Mechanical Properties