Correlation of substructure with mechanical properties of plastically deformed reactor structural materials. Progress report, January 1, 1974--December 31, 1975

Technical Report · Mon Mar 15 04:00:00 EST 1976

DOI:https://doi.org/10.2172/7265765· OSTI ID:7265765

Moteff, J

Ratio of the subgrain boundary dislocations to those contributing to creep deformation was found to be independent of applied stress and creep strain after the steady-state creep stage is reached. The observed cell or subgrain sizes are correlated with flow stress in Type 304 ss, and the deformation rate-stress relation obeys the equation epsilon =..beta.. lambda/sup 3/ (sigma/sub T//E)/sub n/ exp (-Q/sub c//RT), where lambda = subgrain size, sigma/sub T/ = effective true stress, E = Young modulus, and Q/sub c/ = 85 kcal/mole. Well-developed subgrains were observed in TEM on 304 ss tested in creep at 704/sup 0/C. Role of twin boundary-grain boundary intersections in microcracking behavior of 304 ss deformed in slow tension and creep at 650/sup 0/C was investigated. Grain shape analysis show that intragranular deformation becomes more predominant in the grains with the larger intercept distances, and that grain boundary sliding becomes important as the strain rate decreases. RT mechanical properties of austenitic ss are enhanced by subgrains formed during high-temperature deformation. The substructural development during high-temperature low-cycle fatigue of 304 ss was studied using TEM. Fatigue properties of Incoloy 800 tested in bend and push-pull modes are being compared. Effects of hold time on fatigue substructure and fracture of 304 ss are being studied. 31 figures, 53 references. (DLC)

• Research Organization: Cincinnati Univ., Ohio (USA)
• OSTI ID: 7265765
• Report Number(s): COO-2107-11
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ACTIVATION ENERGY
ALLOYS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORRELATIONS
CORROSION RESISTANT ALLOYS
CRACKS
CREEP
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DEFORMATION
DISLOCATIONS
ENERGY
FAILURES
FATIGUE
FRACTURES
GRAIN BOUNDARIES
HARDNESS
HEAT RESISTING ALLOYS
HIGH TEMPERATURE
INCOLOY 800
INCOLOY ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
LINE DEFECTS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
RESEARCH PROGRAMS
STAINLESS STEEL-304
STAINLESS STEELS
STEELS
TWINNING