| Numéro |
J. Phys. Colloques
Volume 51, Numéro C4, Juillet 1990
Multilayer Amorphisation by Solid-State-Reaction and Mechanical Alloying
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| Page(s) | C4-63 - C4-69 | |
| DOI | https://doi.org/10.1051/jphyscol:1990407 | |
J. Phys. Colloques 51 (1990) C4-63-C4-69
DOI: 10.1051/jphyscol:1990407
GENERAL CONDITION FOR AMORPHISATION OF INTERMETALLIC COMPOUNDS
D.L. BEKE1, H. BAKKER2 et P.I. LOEFF21 Department of Solid State Physics, Institute of Physics, L. Kossuth University, H-4010 Debrecen, P.O. Box 2., Hungary
2 Natuurkundig Laboratorium der Universiteit van Amsterdam, Valckenierstraat 65, NL-1018 XE Amsterdam, The Netherlands
Abstract
Using simple thermodynamic considerations for the Gibbs free energies of the crystalline and amorphous states a general condition for the solid-state amorphisation of intermetallic compounds by irradiation or mechanical impact was derived. It was obtained that the amorphisation is possible if the maximum elastic energy, ƊHmel, stored during the (chemical) order-disorder transition is larger than ƊHatop, the enthalpy of the topological change of amorphisation. This condition can be rewritten into the form : the amorphisation is not possible if the order-disorder temperature is lower than the melting temperature, Tc<Tm, and if Tc>Tm - in contrast to Johnson's condition - the possibility of the amorphisation depends on the relative magnitude of the elastic mismatch energy and the chemical energy of ordering. If their ratio is large enough the amorphisation is possible. Detailed calculations, carried out for a large number of compounds, led to a satisfactory agreement with the experimental observations.