Computer Simulation of the Structure Associated with Local Order in Alloys

Modelisation du désordre de substitution bidimensionnel

“…C'est ce qui nousa amen6 fi rediger un tel programme. L'etude de l'ordre fi courte distance dans les alliages metalliques a dejfi conduit ~ la mise au point de methodes informatisees poursuivant le meme but, mais adaptes aux structures cubiques tridimensionnelles (Gehlen & Cohen, 1965;Williams, 1978). Le programme que nous decrivons ici s'en differencie en particulier par la symOtrie hexagonale et la dimensionalite du reseau utilis6.…”

A computer simulation study of local arrangements in disordered molecular crystals

“…The computer program used here is based on the GC concept (Gehlen & Cohen, 1965) modified for use with molecular crystals. We first point out the basic differences between the cubic binary alloys, for which the GC-type simulation has been conventionally used, and disordered molecular crystals.…”

“…It is not easy to visualize the microstructural details from the observed order parameter. For binary alloys, there have been many attempts (Gehlen & Cohen, 1965;Williams, 1976;Gragg, 1970) to generate the local microstructure from a set of order parameters using a digital computer. Though the resulting structure is not unique, there has been considerable empirical evidence (Gragg, Bardhan & Cohen, 1971) indicating it to be a very good statistical representation.…”

Clustering and ordering in solid solutions

“…The deduction of actual defect (or atomic) configurations from SRO parameters is not a determinate problem. In one digital computational method, due to Cohen and co-workers (Gehlen & Cohen, 1965;Gragg, Bardhan & Cohen, 1971), symbols 1 and 0 are exchanged on lattice sites until the computed SRO parameters agree to specified accuracy with the experimentally given ones. The 'experimenter's' task then consists in recognizing typical patterns in the computer output.…”