ENGINEERING INVESTIGATIONS OF CENTRIFUGAL CREEP TESTING MACHINE. Final Report

Technical Report · Fri Feb 01 04:00:00 EST 1963

OSTI ID:4696771

Multi-specimen creep tests can be conducted by centrifugal cantilever bend testing. The deflection-rpm data are convertible into creep-tension values with specimens of tapered design; this is demonstrated with centrifugal creep tests on Al, Fe, and Zircaloy-2. A theory is developed which indicates that creep approaches purely plastic behavior at very low strain rates, and purely elastic behavior at very high strain rates. The applicability of centrifugal creep testing to the study of alloy systems is demonstrated with creep tests on Fe -Al alloys. A centrifugal method for measuring the Young's modulus at elevated temperatures is described. The activation energies for the creep of Fe, Fe -Al alloys, and Zircaloy-2 were obtained by centrifugal bend testing. It is found that the activation energy for Zircaloy-2 increases with increasing stress. Centrifugal creep data on Zircaloy-2 are correlated with conventtonal creep data obtained at Chalk River. Miniaturization tests on Zircaloy-2 were carried out at constant stress by programming the rotational speed. For good data reproducibility, the minimum specimen width should not be less than 0.48 in., and the minimum test head size not less than 3 in. Strains in excess of 1% can be obtained on 18 test specimens simultaneously in a 4 in. diameter test hole (exclusive of space occupied by furnace and casing). A wedge-type test head was developed, which eliminates the need for individual set-screws for attaching test specimens. A preliminary centrifugal bend test program was conducted at 1850 un. Concent 85% F on alumina, ATJ and pyrolytic graphites, and two silicates. Measurable creep with limited scatter was obtained with simple, weighted specimens. The stress-rupture values were measured. However, a more sophisticated specimen design is necessary for avoiding the maximum stress and train localization, with its implied data scatter. The testing should be conducted at considerably higher temperatures in order to obtain significant amounts of creep. (auth)

• Research Organization: Aerojet-General Nucleonics, San Ramon, Calif.
• NSA Number: NSA-17-020400
• OSTI ID: 4696771
• Report Number(s): AGN-8062
• Country of Publication: United States
• Language: English

Related Subjects

ALUMINUM
ALUMINUM ALLOYS
CENTRIFUGATION
CREEP
DEFORMATION
ELASTICITY
GRAPHITE
HIGH TEMPERATURE
IRON
IRON ALLOYS
LABORATORY EQUIPMENT
MATERIALS TESTING
MEASURED VALUES
METALS, CERAMICS, AND OTHER MATERIALS
PLANNING
PYROLYSIS
ROTATION
SILICATES
STRESSES
TENSILE PROPERTIES
YOUNG MODULUS
ZIRCALOY