Short‐Range Order and Atomic Displacements in Ni–20 at% Cr Single Crystals

Ni–20 at% Cr single crystals aged at 741, 828, and 973 K for up to 480 h are investigated by elastic diffuse neutron scattering. The contributions due to short‐range order and atomic size effect are separated by a least‐squares fitting procedure. The short‐range order with diffuse intensity maxima at l 1/2 0 positions increases with decreasing ageing temperature. In comparison, the intensity due to atomic displacements is weak. For the three ageing temperatures investigated the effective pair potentials, determined from the Clapp‐Moss high temperature approximation as well as with an inverse Monte‐Carlo method, are very similar.