SummaryThe surface energies of face·centred and body. centred cubic crystals have been calculated on the assumption that the atoms interact with pairwise potentials of either Morse or Mie type. The calculations take into account interactions between all neighbours and have been carried through for about 50 crystallographically distinct orientations of the surface. No allowance has been made for relaxation of the surface atoms. Stereographic contour plots of the surface energy are presented for four Morse and six Mie potentials in each structure. It is shown that, for all these potentials, a good approximation to the results can be obtained by counting only the numbers of nearest and next-nearest neighbour bonds that are broken and associating empirically determined energies with each of these.

SummarySome recovery processes in metals occur at temperatures too high to be readily accessible to isothermal calorimetric studies and such phenomena are more conveniently inve,stigated using a constant rate of heating. It is shown that the activation energies of these processes can be determined from calorimetric work carried out at a constant rate of heating.

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