J Mater Sci Technol ›› 1999, Vol. 15 ›› Issue (04): 289-295.

• Research Articles •     Next Articles

Mechanical Properties of Si and Some d-electron Metals: Force Laws, Electron Correlation and Bond-breaking

N.H.March   

  1. Oxford University, Oxford, England
  • Received:1999-07-12 Revised:1900-01-01 Online:1999-07-28 Published:2009-10-10
  • Contact: N.H.March

Abstract: The coordination-dependent force field of Tersoff for covalently bonded Si has been used to calculate the cleavage force as a function of interplanar separation and hence to estimate surface energies. This force field is already fitted to density functional results. The relation to bond-breaking and electron correlation will be emphasized. Finnis-Sinclair-type many-body potentials have then been used to treat some d-electron metals. In particular, results for cleavage force in bcc Fe will be presented, and also some calculations as two perfectly planar Fe surfaces are `rubbed together' at different interplanar separations. Finally, lattice dynamical models for the steady-state propagation of a screw dislocation, and then of a crack, will be used, again within a bond-breaking type of force field. For the screw dislocation propagation, a solitary wave equation is shown to follow in the ‘almost continuum' limit. Energy radiated by phonons as the dislocation moves can thereby be calculated.

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