Measurement and Modeling of Resistivity as a Microscale Tool to Quantify the Volume Fraction of Lenticular (alpha)' Particles in a Partially Transformed (delta)-phase Pu-Ga Matrix

We have measured and modeled the change in electrical resistivity due to partial transformation to the martensitic {alpha}{prime}-phase in a {delta}-phase Pu-Ga matrix. The primary objective is to relate the change in resistance, measured with a 4-probe technique during the transformation, to the volume fraction of the {alpha}{prime} phase created in the microstructure. Analysis by finite element methods suggests that considerable differences in the resistivity may be anticipated depending on the orientational and morphological configurations of the {alpha}{prime} particles. Finite element analysis of the computed resistance of an assembly of lenticular shaped particles indicates that series resistor or parallel resistor approximations are inaccurate and can lead to an underestimation of the predicted amount of {alpha}{prime} in the sample by 15% or more. Comparison of the resistivity of a simulated network of partially transformed grains or portions of grains suggests that a correction to the measured resistivity allows quantification of the amount of {alpha}{prime} phase in the microstructure with minimal consideration of how the {alpha}{prime} morphology may evolve. It is found that the average of the series and parallel resistor approximations provide the most accurate relationship between the measured resistivity and the amount of {alpha}{prime} phase. The methods described here are applicable to any evolving two-phase microstructure in which the resistance difference between the two phases is measurable.

[1]  Siegfried S. Hecker,et al.  Phase stability and phase transformations in Pu–Ga alloys , 2004 .

[2]  C. Boehlert,et al.  Phase stability and phase transformations in plutonium and plutonium-gallium alloys , 2004 .

[3]  B. Wirth,et al.  Temperature-dependent defect properties from ion-irradiation in Pu(Ga) , 2004 .

[4]  M. Wall,et al.  Transformation Crystallography and Plasticity of the Delta to Alpha Prime Transformation in Plutonium Alloys , 2003 .

[5]  B. Sadigh,et al.  Effects of Local Solute Ordering and Plasticity on the Delta to Alpha Transformation in Gallium‐Stabilized Plutonium Alloys , 2003 .

[6]  A. Falanga,et al.  Phase transformation in Pu–Ga alloys at low temperature and under pressure: limit stability of the δ phase , 1998 .

[7]  William E Lee,et al.  Ceramic Microstructures: Property control by processing , 1994 .

[8]  C. Roux,et al.  Resistivite electrique des solutions solides d'alliages Pu-Ga en phase δ a tres basses temperatures (4,2–300° K) , 1971 .

[9]  R. O. Elliott,et al.  ELECTRICAL BEHAVIOR BELOW 300 K OF PLUTONIUM-RICH, DELTA-PHASE SOLID SOLUTION ALLOYS CONTAINING CERIUM, ALUMINUM AND ZINC , 1962 .

[10]  C. R. TOTTLE,et al.  Plutonium and its alloys , 1960, Nature.

[11]  C. Daly,et al.  Physical Properties , 2021, Cotton and Flax Fibre-Reinforced Geopolymer Composites.

[12]  J. C. Wolford,et al.  Applied Numerical Methods for Digital Computation , 1985 .

[13]  R. J. Jackson,et al.  X-ray method for measuring percentage of alpha in delta-stabilized plutonium alloys , 1969 .

[14]  J. Anderson,et al.  MEASUREMENT OF ALPHA PHASE PLUTONIUM IN PLUTONIUM-1 w/o GALLIUM ALLOY BY ELECTRICAL RESISTIVITY , 1965 .