Local Arrangements in Fe-31% at. Pd above M_s

Abstract
The diffuse x-ray scattering from an Fe -31 at. pct. Pd single crystal quenched from 1173 K was analyzed to obtain information about the local atomic environment around each atom including the local chemical order and the average atomic displacements from the normal lattice positions. To better reveal the meaning of these average quantities, computer simulations were employed to provide the structure using these values. The results indicate an interconnected distribution of ordered and clustered regions, no more than a few atoms in dimension, and only slightly more developed than for a random arrangement. The pattern of atomic displacements from the average lattice is revealed to be small embryos of a displacement array similar to the FCT martensitic phase and aligned in <110> directions, which may be the premartensitic phase that has been predicted by several authors.