The effect of slightly faster strain rates and internal hydrogen on uranium-0. 8 weight percent titanium alloy mechanical properties

Technical Report · Wed Oct 10 04:00:00 EDT 1990

DOI:https://doi.org/10.2172/6324833· OSTI ID:6324833

Bird, E L

Mechanical testing of uranium-0.8 wt % titanium (U-0.8 wt % Ti) alloys can affect the outcome of mechanical properties, primarily ductility, by varying the crosshead velocity, which changes the strain rate. However, most specifications that govern mechanical properties of this alloy reference ASTM E-8, which limits the speed to 0.5 in./in. of gage length per minute. Our current procedure for testing U-0.8 Ti is not at the maximum speed permitted in ASTM E-8, so an experiment was designed to evaluate the effect of maximizing the crosshead velocity per ASTM E-8. In order to create a fair assessment, tensile specimens were prepared that were low in internal hydrogen (0.02 ppM) and higher in internal hydrogen (0.36 ppM). External hydrogen effects were minimized by testing in a controlled environment that contained less than 10% relative humidity. Test results showed that for the low hydrogen test group, increasing the crosshead velocity caused a significant increase in reduction in area (RA), but not in elongation. For the higher hydrogen test group, increasing the speed resulted in a significant increase in RA and an increase, though not statistically significant, in elongation. Of equal importance was an observation that strongly suggests a correlation between material defects, like inclusion clusters, and higher hydrogen content, especially at the slower strain rate that would explain the erratic behavior in ductile properties associated with this alloy. As a result of this study, increasing the crosshead velocity to 0.32 in./min is recommended for mechanical testing of U-0.8 Ti alloys. 9 refs., 4 figs., 5 tabs.

• Research Organization: Oak Ridge Y-12 Plant, TN (USA)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: AC05-84OS21400
• OSTI ID: 6324833
• Report Number(s): Y/DV-987; ON: DE91004376
• Country of Publication: United States
• Language: English

Related Subjects

050700* -- Nuclear Fuels-- Fuels Production & Properties
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
ACTINIDE ALLOYS
ALLOYS
CRACK PROPAGATION
DUCTILITY
ELEMENTS
HYDROGEN
MATERIALS TESTING
MECHANICAL PROPERTIES
MECHANICAL TESTS
NONMETALS
STRAIN RATE
TENSILE PROPERTIES
TESTING
TITANIUM ADDITIONS
TITANIUM ALLOYS
URANIUM ALLOYS