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Book Transformation Kinetics of Plutonium

Download or read book Transformation Kinetics of Plutonium written by R. D. Nelson and published by . This book was released on 1961 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Transformation Kinetics of Plutonium

Download or read book Transformation Kinetics of Plutonium written by R. D. Nelson and published by . This book was released on 1958 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Transformation Kinetics of Plutonium

Download or read book Transformation Kinetics of Plutonium written by R. D. Nelson and published by . This book was released on 1961 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Transformation Kinetics of Plutonium

Download or read book Transformation Kinetics of Plutonium written by and published by . This book was released on 1961 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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/ cm3to 19.70 to 19.75 g/cm3. 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).

Book Transformation Kinetics of Plutonium Part II a Study of the Gamma to Beta to Alpha and Alpha to Beta to Gamma Transformations

Download or read book Transformation Kinetics of Plutonium Part II a Study of the Gamma to Beta to Alpha and Alpha to Beta to Gamma Transformations written by and published by . This book was released on 1958 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The kinetics of the gamma deg C was con- beta deg C was con- alpha, beta deg C was con- gamma, and alpha deg C was con- beta deg C was con- gamma transformations were determined with a fiuid displacement technique. The rates of formation of the alpha and beta phases from the gamma phase were determined after gamma heat treating and allowing a sample to traasform isothermally in the alpha and beta ramges. Isothermal reaction curves were obtained from 160 C to -78C. The time-temperature-transformation curve of the gamma deg C was con- beta deg C was con- alpha transformation was plotted. The effect of the gamma heat treating time and temperature on the rate of transformation was examined. Isothermal reaction curves and time-temperature- transformation curves of the beta deg C was con- gamma, and alpha deg C was con- beta deg C was con- gamma transformations were plotted. Photomicrographs of specimens having transformed from the gamma range at different rates of transformation are presented. (auth).

Book Kinetics of the Beta alpha Transformation in Pure Plutonium

Download or read book Kinetics of the Beta alpha Transformation in Pure Plutonium written by and published by . This book was released on 1965 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Transformation Kinetics of Plutonium Part I a Study of the Beta to Alpha and Alpha to Beta Transformations

Download or read book Transformation Kinetics of Plutonium Part I a Study of the Beta to Alpha and Alpha to Beta Transformations written by and published by . This book was released on 1958 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The transformation kinetics of alpha and beta plutoniunn were determined by using a fluid displacement technique. The rate of formation of the alpha phase from the beta phase was determined after beta heat treating and allowing the sample to transform isothermally in the alpha range. Isothermal reaction curves were obtained from --78 to +90 d C.A time- temperaturetransformation curve showed the maximum rate of transformation to be approximately --20 d C. The beta phase did not transform completely to the alpha when the transformation was allowed to take place isothermally. A relationship between the fraction untransformed beta and the transformation temperature has been established. Isothermal reaction curves and a time- temperature-transformation curve of the alpha at 200 deg C an - BETA transformation were obtained. Portions of the timetransformation curves of the BETA at 200 deg C an alpha transformation of four purities were plotted. The effects of beta heat treating times and temperatures were studied. Photomicrographs of a specimen having transformed from the beta to the alpha phase at different rates of transformation are presented. (auth).

Book THERMODYNAMICS AND KINETICS OF PHASE TRANSFORMATIONS IN PLUTONIUM ALLOYS

Download or read book THERMODYNAMICS AND KINETICS OF PHASE TRANSFORMATIONS IN PLUTONIUM ALLOYS written by Z. Liu and published by . This book was released on 2004 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this report we investigate order, stability, and phase transformations for a series of actinide-based alloys. The statics and kinetics of precipitation and ordering in this class of alloys are modeled with a scheme that couples fundamental information on the alloy energetics obtained from experimental and assessed thermo-chemical data to the CALPHAD approach commonly used in industry for designing alloys with engineering specificity with the help of the Thermo-Calc software application. The CALPHAD approach is applied to the study of the equilibrium thermodynamic properties of Pu-based alloys, Pu-X, where X=Al, Fe, Ga. The assessment of the equilibrium phase diagrams in the whole range of alloy composition has been performed with the PARROT module of the Thermo-Calc application software. Predictions are made on the low temperature and Pu-rich side of the phase diagrams of Pu-Ga and Pu-Al for which controversy has been noted in the past. The validity of the assessed thermo-chemical database will be discussed by comparing predicted heats of transformation for pure Pu with measured values from differential scanning calorimetry analysis. An overall picture for the stability properties of Pu-Ga and Pu-Al that reconciles the results of past studies carried out on these alloys is proposed. Results on phase stability in the ternary Fe-Ga-Pu and Al-Fe-Pu alloys are discussed. The information collected in this study is then used to model metastability, long-term stability and aging for this class of alloys by coupling Thermo-Calc with DICTRA, a series of modules that allow the analysis of DIffusion Controlled TRAnsformations. Kinetics information is then summarized in so-called TTT (temperature-time-transformations) diagrams for the most relevant phases of actinide alloys. Specifically, results are presented on kinetics of phase transformations associated with the eutectoid-phase decomposition reaction occurring at low temperature, and with the martensitic transformation that takes place at low Ga content in Pu-Ga alloys. Finally, after a summary of the most salient results, suggestions are made for further studies at the micro- and mesoscales.

Book The Kinetics of the Beta to Alpha Transformation in Unalloyed Plutonium Using Differential Scanning Calorimetry

Download or read book The Kinetics of the Beta to Alpha Transformation in Unalloyed Plutonium Using Differential Scanning Calorimetry written by and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Differential scanning calorimetry measurements, both isothermal and on cooling, were made during the [beta] → [alpha] transformation of unalloyed plutonium. The calorimetric measurements, because they directly measure the rate of heat flow, provide a direct quantitative measure of the rate of the reaction. Isothermal measurements at temperatures from 56° to 68°C showed that the reaction required incubation times, presumably for nucleation of the alpha phase, of from 300 to 550 seconds. The reaction rate increased with decreasing temperature in agreement with results of prior studies. The measured value for the heat of the reaction also corroborated earlier findings. The fraction-transformed curves were analyzed using the Johnson, Mehl, Avrami model. Analysis showed clearly that the reaction kinetics do not fit this model. The Avrami exponent, instead of being constant as predicted, decreased continuously (by more than a factor of four) during the first 80% of the reaction. Possible reasons for this apparent deviation from classical transformation kinetics are discussed. Measurements in the temperature-scanning mode were made on a sample consisting of ten separate pieces of plutonium. With successive cooling cycles through the [beta] → [alpha] transformation, the heat release peak changed in shape, width, and position. This effect is believed to be due to changes in the residual stresses in different pieces of the sample.

Book Microstructure and Kinetics of the Plutonium beta Yields alpha and gamma Yields alpha Transformations

Download or read book Microstructure and Kinetics of the Plutonium beta Yields alpha and gamma Yields alpha Transformations written by and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Supported-discharge cathodic etching and SEM examination techniques were developed for $alpha$-Pu and used to investigate the $alpha$ microstructures formed by the $beta$/sub $alpha$/ $Yields$ $alpha$ and $beta$/sub $gamma$/ $Yields$ $alpha$ transformations in high-purity extruded Pu at low and high $alpha$-phase temperatures ($beta$/sub $alpha$/ and $beta$/sub $gamma$/ are $beta$ formed from $alpha$ and $gamma$, respectively). Low (200$sup 0$K) $beta$/ sub $alpha$/ $Yields$ $alpha$ transformation temperatures produced $alpha$ with a grain size that was finer than that of the original extruded $alpha$ and substantially smaller than the grain size of the $alpha$ formed from $beta$/sub $gamma$/. At high $alpha$-phase temperatures (343 to 370$sup 0$K), $beta$/sub $alpha$/ transformed to $alpha$ by the surface nucleation and inward growth of colonies of columnar $alpha$ grains oriented radially with respect to the original nucleation site. The transformation kinetics could be correlated with the microstructural observations based on a correspondence between the long axes of the grains and the (010) direction of the monoclinic $alpha$-Pu structure. Significant changes in the size, shape, and orientation of the $alpha$ grains were noted with increasing transformation temperature. Conversely, the grain size of the $alpha$ formed from $beta$/sub $gamma$/ was essentially constant at all transformation temperatures. Metallographic evidence of the $gamma$ $Yields$ $alpha$ skip transformation or a significant change in the mode of the $gamma$ $Yields$ $alpha$ transformation was obtained by a comparison of the $alpha$ microstructures produced by quenching $gamma$ to high (362 to 368$sup 0$K) and low (200$sup 0$K) $alpha$-phase temperatures. (auth).

Book Reaction Between Plutonium and Deuterium

Download or read book Reaction Between Plutonium and Deuterium written by David F. Bowersox and published by . This book was released on 1974 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Chemistry Purification and Metallurgy of Plutonium

Download or read book The Chemistry Purification and Metallurgy of Plutonium written by Charles Allen Thomas and published by . This book was released on 1944 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: