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Flexible Films
Published in Martin W. Jawitz, Michael J. Jawitz, Materials for Rigid and Flexible Printed Wiring Boards, 2018
Martin W. Jawitz, Michael J. Jawitz
Rolled foils are different in every way from ED copper. This foil is very flexible and should be used in dynamic applications that require constant flexing. RA copper is manufactured by melting the cathode copper (which is produced electrolytically) and then formed into large ingots. This direct chill casting method allows for controlled solidification that provides continuous purity, monitoring, and grain size selection and also eliminates existing defects such as voids that would influence the quality of the foil when it is rolled into the final form. Because this process starts with copper ingots and has longer production cycles with incremental approaches to the final thickness, rolling results in a foil with horizontal grain orientation and smooth surfaces on both sides. Roll reduction quickly causes work hardening, with the result that rolled foils must be periodically annealed. They are sold in several degrees of hardness from “as rolled” to dead “soft.” Rolled annealed is the standard anneal condition that provides good flexural endurance and resistance to fracturing in dynamic use, which is typical of flexible printed wiring boards.
Alloying of U-Al-SS as a Simulant for Pu-Al-SS Alloying
Published in Nuclear Technology, 2022
L. C. Olson, R. A. Pierce, H. M Ajo
The U-, Pu-, and Zr-rich regions that can form are not obvious and are dependent on the concentrations of those elements in the interdendritic regions, which are also dependent on cooling rates. Slower cooling allows for more stable phases to form. Faster cooling, such as chill casting, could suppress the formation of multiple phases. In binary alloys, Pu can form stable PuNi2 and PuFe2 phases that melt at approximately 1210°C and 1240°C, respectively, but also lower melting point eutectics that can melt at approximately 413°C to 415°C (Ref. 12). Considering the low levels of actinides being added to the steel, they would be difficult to remove from the surrounding steel without melting it. Based on the SS-U SEM/EDS analysis to date, which will be discussed, it does not appear that the low melting point actinide eutectics formed.