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The investigation of ordering in binary substitution alloys with f.c.c. lattice, in which magnetic ordering can exist along with the f.c.c. structure is performed in second approximation of the Kirkwood method. It is shown that the exchange interaction essentially effects the development of atomic ordering. The possible types of phase diagrams are investigated. It is shown that the correlation considered makes a correct description possible of the kind of order-disorder phase transition in the alloys of L1 superstructure. The correlation contributions to the heat capacity of alloys are calculated.In zweiter Naherung der Kirkwoodmethode wird eine Untersuchung der Ordnung in binaren Substitutionslegierungen mit k.f.2.-Gitter durchgefiihrt, in denen magnetische Ordnung zusammen mit der k.f.z.-Struktur existiert. Es wird gezeigt, daB die Austauschwechselwirkung die Entwicklung atomarer Ordnung wesentlich beeinfluBt. Die moglichen Typen der Phasendiagramme werden untersucht. Es wird gezeigt, daD Korrelationsberiicksichtigung eine korrekte Beschreibung der Art des Ordnungs-Unordnungs-Phaseniibergangs fur die Legierungen der L1-Superstruktur ermoglicht. Die Korrelationsbeitrage zur Warmekapazitat der Legierungen werden berechnet.

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The results are given of 57Fe Mössbauer investigations of the Ni3(Fe1−xMnx) alloy system (0 ≦ x ≦ 0.9) in three different states (after cold rolling, thermal disordering, and annealing). The existence of the ternary Ni6FeMn superstructure reported earlier is not confirmed. For 0.7 ≦ x < 1 a second type of iron atom neighbour shell appears which probably relates to two states of Mn atoms in the alloys. An addition of one Mn in the Fe nearest neighbours leads to a decrease of the hyperfine field on Fe nuclei, indicating the antiferromagnetic character of FeMn interactions. However, substitution of the Fe atom in the second coordination shell by Mn increases the effective field on the resonant nucleus by 3.6 × 105 A/m on the average. It is shown that various heat treatments do not destroy the magnetic texture in a specimen and the short‐range order formed by quenching. This explains some earlier results.