Transformation enthalpies in beryllium

The enthalpy of the solid state transformation and the enthalpy of fusion have been measured for beryllium of various purities using the method of differential thermal analysis. The results, 505 cal mol-1 for the α-β transition at 12790C and 577 cal mol-1 for the β-liquid transition at 12900C, are markedly lower than the published figure of 3520 cal mol-1 for the combined transitions. This disparity is believed to derive from the different techniques used (dynamic drop calorimetry and equilibrium DTA) which give rise to real behavioural changes. (Auth.)