Alloy Material from Rocky Flats.

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alb THIS DOCUMENT CONSISTS OF_ 1 _PAGES Central File No, Released through the MOUND ISDR PROJECT Record Copy held at Mound Facility University of California Lawrence Radiation Laboratory We received from Rocky Flats on Transfer Number STJ-SBX-51P the alloy material which you had ordered. The two items arrived satisfactorily in the forms as requested. The weight of the tantalum container for the one item was not recorded. Only the weight of the alloy, 132 grams, was stated. Can you obtain more exact information on the weight of the alloy or the tantalum? The exact composition of this material is needed since a small variation in weight per cent composition results in a larger deviation in atomic per cent. The smaller alloy sample was examined by differential thermal analysis. A copy of the actual DTA trace is included. The temperatures of the recorded phase transformations are listed in the accompanying table. The interpretation of the DTA data is based on the phase diagram which appears in LA-2312. The only transformation which appears in conflict with the phase diagram is the one at 396'. This transition gives a sharp DTA peak, which is similar to the results obtained with other solid state phase transformations. This reaction is probably due to the seta to seta-prime transition of Pu liGa which is listed at 363 ° on the LASL phase diagram. According to that phase diagram, this phase is not expected to be present. Possibly the solid solution line for delta plutonium is in error in the diagram, or the composition of the alloy examined is greater than one weight per cent gallium. conia: re ed c!ata a defined e disclosure of its con'en:s :n any manner to tin Unauthorized person is prohibired.

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or Fuels Section Mr. Hank Weiss -2- July 12, 1962 Based on the foregoing information, the heat capacity determinations will be made at 100 . intervals up to 500 . 0 with additional measurements made immediately below and above 396 . . If the reaction at this temperature is the zeta to seta-prime phase change, in Pu 3Ga, the heat of the transformation will be measured. For a first-order phase reaction of this type we expect very little difference in the heat capacity above and below this temperature. As an example, only small differences have been observed in the specific heats of the many phases of unalloyed plutonium. A large change in heat capacity would be expected if the alloy went through a second-order phase reaction, such as at the Curie point of nickel, but this type of transformation was not indicated from the DTA examination. The calorimeter has been calibrated for this determination and the heat capacity determination on the alloy is in progress this week. As soon as additional information is developed, I will forward it

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380 - supercooled see discussion 508 start of delta to epsilon two delta to epsilon two phase area start of melting completion of melting