TRANSFORMATION KINETICS OF PLUTONIUM. PART III

Technical Report · Fri Dec 01 04:00:00 EST 1961

DOI:https://doi.org/10.2172/4819065· OSTI ID:4819065

Nelson, R. D.

Isothermal reaction curves and T-T-T curves showing the effect of different variables on the beta-alpha transformations in plutonium are presented. Impurity content, stresses, beta heat-treating time and temperature, hydrostatic pressing, specimen size, and thermal cycling influenced the kinetics of the beta- alpha transformation. Decreasing the impurlty content increased the rate of transformation. High tensile stress retarded the beta-alpha transformation. Increasing the beta heat-treating time and temperature markedly decreased the rate of transformation. Hydrostatic pressing at 90,000 psi accelerated the beta- alpha transformation under pressure but decreased any subsequent beta-alpha transformations by as much as two orders of magnitude. Specimen size had no effect on the start of the transformation but increasing the specimen size from 0.010 to 0.37 inch decreased the rate of completion of transformation several orders of magnitude. Thermal cycling less than 15 cycles did not affect the rate of transformation. The density of high purity plutonium during hydrostatic pressing at l80 deg C and cooling under pressure increased from 19.60 to 19.65 g/ cm/sup 3/to 19.70 to 19.75 g/cm/sup 3/. This increase was shown to be attributed to decreasing the volume of microcracks rather than transformation of any metastable beta phase. A T-T-T curve of the alpha-beta transformation is given which shows the start of the transformation is 16 hours at 116.5 deg C with the rate decreasing extremely rapidly with decreasing temperature. The times for the start and completion of the transformation were significantly shorter than the early work reported. The faster rate was attributed to less impurities, The gamma-beta-alpha and alpha-beta-gamma transformations are discussed also. Isothermal reaction curves and T-T-T curves for these transformation are included. (auth)

• Research Organization: General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
• DOE Contract Number: AT(45-1)-1350
• NSA Number: NSA-16-007886
• OSTI ID: 4819065
• Report Number(s): HW-70859
• Country of Publication: United States
• Language: English

Related Subjects

ALLOTROPY
CRACKS
DIAGRAMS
HEAT TREATMENTS
IMPURITIES
METALS, CERAMICS, AND OTHER MATERIALS
PHASE TRANSFORMATION
PLUTONIUM
PLUTONIUM-ALPHA
PLUTONIUM-BETA
PLUTONIUM-GAMMA
PRESSURE
REACTION KINETICS
STRESSES
THERMAL CYCLING
VOLUME