Internal friction in Fe-Ga alloys at elevated temperatures

The paper studies amplitude-independent thermally-activated and transient effects in as-cast Fe-(8–33)%Ga alloys in a temperature range from 0 to 600 °C and frequencies from 0.1 to 30 Hz using a dynamic mechanical analyser. The origin of the recorded anelastic effects is discussed based on both earlier publications and new, most systematic, data obtained in this paper. Activation energies and characteristic relaxation time are evaluated and analysed to conclude about the influence of Ga content on Zener relaxation, possible overlapping of Snoek-type relaxation with another, still not well defined, mechanism. The transient effect along with a sharp increase in the modulus is a sensitive tool to detect transition from metastable to stable structure in the Fe-Ga alloys.