Test of Some Statistical Approximations (Quasi Chemical, Cvm) in Bcc and Fcc Binary Alloys by Monte Carlo Simulation. Validity Range of the Clapp and Moss Approximation.

In the framework of regular solution model, we test the validity of some usual approximations (QC, CVM) of entropy in (disordered) binary alloys by Monte Carlo simulation. The validity range of these approximations are explored both in alternant and nonalternant lattice with ferro- and antiferromagnetic coupling. The CVM tetrahedron approximation is also analysed on a structure containing only tetrahedra: the 120 polytope [8] in 3d curved space.