Semi-empirical models describing thermodynamic properties of f-metals

“…Instead, we have used the equation for the previously developed invar model [13] as an interpolation function for the experimental data. Elkin et al [10] and Lawson et al [5] first showed that the AP model would work for Pu, and now we have used the Levenberg-Marquardt procedure to optimize the AP parameters. The resulting fits are shown in figure 6, and the fit parameters in table 3.…”

Section: Thermal Expansion Of Pu-ga Alloysmentioning

confidence: 99%

“…The second equality in (10) follows from [7]. In addition, as discussed in [16], there is a Grüneisen term…”

Section: Temperature Dependence Of the Bulk Modulus Ofmentioning

confidence: 99%

“…In section 3, we fit the measured thermal expansions of Ce 0.9−x La x Th 0.1 alloys to the AP model and extract values of the AP parameters E, S, V and U for these alloys. In section 4 we fit the measured thermal expansion of Pu-Ga alloys, as first suggested in [5] and [10], and extract the AP parameters. In section 5 we apply the AP model in fitting the temperature dependence of the bulk modulus of a δ-phase Pu alloy.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal expansion and transformation behavior of cerium and plutonium alloys: an application of the Aptekar–Ponyatovsky regular solution model

Lawson¹,

Lashley²

2011

J. Phys.: Condens. Matter

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In this paper we apply the Aptekar-Ponyatovsky (AP) regular solution thermodynamic model to the analysis of experimental data for the coefficient of thermal expansion (CTE) and determine the AP model parameters for unalloyed cerium metal, Ce-Th-La alloys, and Pu-Ga alloys. We find that the high temperature CTE of cerium metal follows the predictions of the AP model based on low temperature, high pressure data. For Ce-Th-La alloys we use the AP parameters to track the suppression of the first-order γ-α cerium transition. We show the AP model accounts for the negative CTE observed for Pu-Ga alloys and is equivalent to an earlier invar model. Finally, we apply the AP parameters obtained for Pu-Ga alloys to rationalize the observed δ-α transformation pressures of these alloys. We show that the anomalous values of the Grüneisen and Grüneisen-Anderson parameters are important features of the thermal properties of plutonium. A strong analogy between the properties of plutonium and cerium is confirmed.

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