Thermally activated and transient anelasticity due to phase transitions in Fe-27Ga alloy

Transient and thermally activated anelastic effects between 0 and 800 °C are studied in in a Fe-26.6at%Ga alloy using bending and torsion forced vibrations and measuring the mechanical loss ant the elastic modulus. The structure characterization and transformations are studied by in situ neutron diffraction. The phase morphology and grain crystal structure are investigated by EBSD. Vibrating sample magnetometry accompanies those measurements providing the magnetic susceptibility that characterize the phases appearing as a function of the temperature. Two thermally activated and three transient anelastic effects are reported. They are discussed in detail with respect to structure and phase transitions in the alloy. Four main phases are found: D03, L12, D019 and A2. Each transformation between these phases is characterized by a transient mechanical loss peak and a modulus variation. The thermally activated relaxations named P1 and P2 are respectively a Snoek and a Zener relaxations and they are related to the presence of the metastable D03 phase.