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Method for the prediction of the hydriding thermodynamics of ternary PD-based alloys.

Description: A method has been developed to calculate the hydriding thermodynamics of ternary Pd-X-Y systems, where X and Y are substitutional alloying elements, by using the properties of the binary Pd-X and Pd-Y systems. Experimental data was collected on the Pd-Rh-Co system to test the validity of this method. Hydrogen pressure-composition isotherms of several binary Pd-Rh and Pd-Co alloys and Pd-Rh-Co ternary alloys were measured to determine the thermodynamics of hydrogen absorption, hydride formation and decomposition, and hydrogen capacity. Good agreement between the calculated and measured values for the ternary Pd-Rh-Co system, in the dilute alloying regime (< 10 at.% total alloying additions), was obtained using our method. Examining literature results on other ternary Pd-X-Y systems checked the universality of this method. Again, the method succeeds in predicting the hydriding thermodynamics for both lattice contracted and lattice expanded alloy systems, Pd-Ni-Rh and Pd-Ag-Y respectively.
Date: January 1, 2001
Creator: Teter, D. F. (David F.) & Mauro, M. E. (Michael Ernest)
Partner: UNT Libraries Government Documents Department

Grain refinement in beryllium by equal channel angular extrusion.

Description: Ultrafine-grained Be is the material of choice for fabrication of the NIF target capsules. One method of producing ultrafine grains in metals is by imposing very large strains. Equal channel angular extrusion (ECAE) has been used to achieve these high strains. Previous work has shown that powder-source Be can be successfully processed by ECAE. Pure Be and Be-0.9 at% Cu alleys have been arc melted and cast into billets 5 mm in diameter by 30 mm in length. These billets were enclosed in cans fabricated from commercial purity Ni, with an electron-beam welded end plug. These cans were extruded at 425C in ECAE tooling with a 120' angle between the inlet and outlet channels. The billets were extruded up to 4 times. The microstructures of the powdersource Be and the arc-melted Be and Be-0.9 at% Cu materials will be presented, and the effects of the ECAE processing on the grain size will be discussed.
Date: January 1, 2003
Creator: Alexander, D. J. (David J.); Mauro, M. E. (Michael Ernest); Cooley, J. C. (Jason C.) & Dauelsberg, L. B. (Lawrence B.)
Partner: UNT Libraries Government Documents Department