Short-range order effect

To summarize we have reproduced the intricate structural properties of the Fe-Co, Fe-Ni and the Fe-Cu alloys by means of LMTO-ASA-CPA theory. We conclude that the phase diagram of especially the Fe-Ni alloys is heavily influenced by short range order effects. The general trend of a bcc-fcc phase transition at lower Fe concentrations is in accordance with simple band Ailing effects from canonical band theory. Due to this the structural stability of the Fe-Co alloys may be understood from VGA and canonical band calculations, since the common band model is appropriate below the Fermi energy for this system. However, for the Fe-Ni and the Fe-Cu system this simple picture breaks down. 

Essentially disordered Stabilization by short-range ordering effects Partial order random stacking sequences, etc. Complete ordering long-range interactions... 

Fig.5. Calculated solute surface concentrations for Ni-8at%Al-4at%Cu(l 11) thick solid lines - FCEM, thin solid lines - the BW-type approximation. Dashed-dotted lines - solute surface concentrations for the binary alloy Ni-8at%Al(lll) and Ni-4at%Cu(l 11) surfaces calculated in the FCEM approximation. Note the enhancement of Cu segregation induced by ternary alloying and short-range order effects.

De Gennes, P.G. Phenomenology of short-range-order effects in the isotropic phase of nematic materials. Phys. Lett. 1969,35A, 454-455. 

Short-range order effects in the isotropic phase... 

The pumping and filtration procedure serves another purpose in addition to filtration. The movement of the slip through a tube and then through a filter also keeps the slip fluid. This is known as shearthinning the viscosity actually decreases as a function of the shear rate. The physics of this phenomenon is described in Section 4.2. Slip that is not kept in motion tends to form "short-range order —that is, it tends to thicken. This will also be described in more detail later in this chapter. The pumping and filtration process keeps the slip fluid and prevents the formation of this short-range order effect. 

De Gennes PG (1971) Short range order effects in the isotropic phase of nematics and cholesterics. Mol Cryst Liq Cryst 12 193... 

P. G. de Gennes, Short Range Order Effect in the Isotropic Phase of Nematics and Cholesterics, Mol. Cryst. Liq. Cryst, 12, p. 193 (1971). 

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