Structural-Phase Сhanges During the D1a→A1 Phase Transition in the Ni4Mo Alloy

The results of studying the structural and thermal effects in region D1a→A1 order-disorder phase transition Ni4Mo alloy are presented. It is found that occurs a narrow temperature range 16 °C while long-range order parameter п this decreases from 1 to 0.85 and, upon reaching ТК, abruptly 0. Studying allows obtaining dependence specific heat Ср(Т) obtained determination enthalpy entropy alloy. main contribution transformation configurational. nonconfiguration not large contributes ordering processes. established beginning deviation on Cp(T) linear one correlates with formation two-phase state D1a +A1 decrease atomic D1a. Based calculations based first principles thermodynamic parameters compounds, Ni-Mo system obtained. most stable compound Ni3Mo. Theoretical give value -8.3 kJ/mol.