Deformation and Fracture Properties in Neutron Irradiated Pure Mo and Mo Alloys

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2008.03.004· OSTI ID:933050

Byun, Thak Sang ^[1]; Li, Meimei ^[1]; Cockeram, Brian V ^[2]; Snead, Lance Lewis ^[1]

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1. ORNL
2. Bechtel-Bettis, Inc.

The effect of neutron irradiation on the mechanical properties of select molybdenum materials, pure low carbon arc-cast (LCAC) Mo, Mo-0.5% Ti-0.1% Zr (TZM) alloy, and oxide dispersion-strengthened (ODS) Mo alloy, was characterized by analyzing the temperature dependence of mechanical properties. This study assembles the tensile test and analysis data obtained through multiple series of irradiation and post-irradiation experiments. Tensile specimens in stress-relieved conditions with longitudinal (LSR) and transverse (TSR) directions were irradiated in high flux isotope reactor (HFIR) at temperatures ranging 270 to 1100oC to 0.6 -13.1 dpa. Also, the recrystallized LCAC Mo specimens in the longitudinal direction (LR) were also irradiated up to 0.28 dpa at ~80oC. Tensile tests were performed at temperatures ranging from -194 oC to 1400oC. Analysis results indicate that the irradiation at temperatures below 700oC increased strength significantly, up to 170%, while the increase of yield stress by irradiations at higher temperature was not significant. The plastic instability stress was strongly dependent on test temperature but was nearly independent of irradiation dose and temperature. The true fracture stress was dependent on test temperature to a lesser degree than was the yield stress and plastic instability stress. It was also slightly impacted by irradiation, depending on both irradiation and test temperatures. Brittle fracture often occurred in the LSR specimens tested at room temperature or lower after low temperature irradiation, while it was observed in many irradiated TSR specimens over the whole test temperature range. The ODS-LSR specimens showed the highest resistance to irradiation embrittlement due to relatively higher fracture stress. The critical temperature for shear failure (CTSF) was defined and evaluated for the materials, and the CTSF values were compared with the ductile to brittle transition temperatures (DBTT) based on ductility data.

• Research Organization: Oak Ridge National Laboratory (ORNL); High Flux Isotope Reactor
• Sponsoring Organization: ORNL work for others
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 933050
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Journal Issue: 2 Vol. 376; ISSN 0022-3115; ISSN JNUMAM
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALLOYS
CARBON
CRITICAL TEMPERATURE
DEFORMATION
DUCTILITY
EMBRITTLEMENT
FRACTURE PROPERTIES
FRACTURES
HFIR REACTOR
INSTABILITY
IRRADIATION
MECHANICAL PROPERTIES
MOLYBDENUM
NEUTRONS
OXIDES
PLASTICS
SHEAR
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE