Structural studies of decomposition in Fe–x at.%Ga alloys

Decomposition in Fe–x at.%Ga alloys subjected to different thermal treatments has been investigated by high-resolution X-ray and neutron diffraction for 12 < x < 25. Quenching suppresses the formation of a D03 structure in favor of a high-temperature disordered bcc (A2) structure. By contrast, annealing produces a two-phase mixture of A2 + D03 for 14 < x < 20 and a fully D03 phase for x = 25. Temperature dependent studies revealed that phase separation occurs below 650 °C on cooling for x = 20, where a notable radial line broadening develops. The splitting of the (2 0 0) and (0 0 2) Bragg peaks observed along the respective transverse directions indicates that the samples are composed of multiple crystal grains, slightly tilted with respect to each other.