AN INTERNAL FRICTION STUDY OF ALLOTROPIC TRANSFORMATIONS OF PLUTONIUM, URANIUM AND COBALT

Consistent correlations on plutonium, uranium and cobalt have been made which suggest that internal friction and relative shear modulus measurements can be used for the classification of the mechanisms of allotropie transformations. Diffusional transformations were characterized by the fact that the internal friction values of the parent and product phases were considerably different at the transformation temperature and the relative shear modulus changed over a very narrow temperature range of 2-3 °C. Shear transformations were characterized by the fact that the internal friction values above and below the transformation temperature were approximately equal, and the relative shear modulus changed over a broad temperature range. Possible interpretations for these observations are given. In addition, features of the steady state internal friction curves of plutonium, uranium and cobalt are discussed. © 1969.