The effects of trace element additions on the microstructure and age-hardening properties of Pb-Ca and P b -C a -S n alloys for maintenance-free batteries are reported. A specific laboratory casting procedure duplicating grid solidification conditions and the solidification-cast property relationships upon which it is based are discussed. It was found that bismuth, antimony, copper, and silver in amounts typical of high bismuth primary and refined secondary base leads have little or no influence on microstructure in Pb-0.085Ca and P b -0.085Ca-0.8Sn. The addition of trace elements increased the early hardness of Pb-0.085Ca-0.8Sn but had no effect in Pb-0.085Ca. * Electrochemical Society Active Member. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.173.72.87 Downloaded on 2014-12-26 to IP

Microstructure, hardness, castability, and hydrogen evolution rate of cast SLI battery grids were determined for a wide range of Pb‐Ca and Pb‐Ca‐Sn alloy compositions. Calcium oxidation rate of the molten alloys was also studied. These properties were determined as a function of alloy composition, trace element content, and casting conditions. Grids were cast on a commercial calcium‐lead grid casting machine under production conditions. Grids were cast from two base leads: a low bismuth primary lead and a refined secondary lead containing bismuth, antimony, copper, and silver. Calcium was found to affect hardness and initial aging rate, while tin influenced grain size, castability, and calcium oxidation rate. Hydrogen evolution rate was also found to be a function of alloy composition. Trace element additions influenced hardness and hydrogen evolution in Pb‐Ca‐Sn alloys, and calcium oxidation rate and castability in Pb‐Ca alloys. Casting conditions influenced grain size and hardness at some alloy compositions.

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This work has undergone a double-blind review by a minimum of two faculty members from institutions of higher learning from around the world. The faculty reviewers have expertise in disciplines closely related to those represented by this work. If possible, the work was also reviewed by undergraduates in collaboration with the faculty reviewers. AbstractAlloy 617, a nickel-based alloy, is a leading candidate for application in next-generation nuclear plants (NGNPs). Creep, a thermally activated, time-dependent deformation process impacts the lifetime and failure of heat exchangers used at the very high operating temperatures and pressures of such plants. Current methods of testing creep are generally limited to bar specimens in uniaxial tension. In an attempt to correlate uniaxial to multiaxial creep behavior a method to test creep in a pressurized tube was developed. Test specimens were pressurized with argon up to 3.5 MPa, and heated to 950°C. Creep rates were measured as strain rates by tracking diametric changes with time. Parallel experimental and modeling efforts were used to characterize creep behavior in the pressurized tubes. The aim of this research was to use the existing body of knowledge concerning creep in Alloy 617 to develop a model to accurately predict creep in tubular components. Towards this end, a constitutive model was developed and computer simulations undertaken which were ultimately verified experimentally.

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