Abstract
Measurements of the temperature dependence of the dynamic elastic modulus E and internal friction Q^β1^ are reported from 25β900 Β°C at frequencies near 1 kHz for an alloy of Fe β 24.8 atom% Al. The influence of ferromagnetism on E and Q^β1^ is investigated using a variable direct current magnetic field of 0β1500 Oe. Ambient temperature measurements as a function of field strength exhibit an influence from macroβeddy current damping and magnetoβelastic hysteresis in agreement with theory. A DL E effect, of maximum magnitude 0.06, is reported for measurements of E (for H = 0 and H = 1500 Oe) as a function of temperature. This modulus defect disappears at approximately 500 Β°C in agreement with reported measurements of the longitudinal magnetostriction. A small modulus maximum at 540 Β°C is reported with even the highest applied fields. Two possible explanations are presented. Anelastic measurements show three damping maxima: a Snoek peak due to interstitial carbon at βΌ 250Β° C, a Zener peak and a grain boundary peak near 700 Β°C. The values of Q for the first two are 23 kcal/mol and 61 kcal/mol respectively, and corresponding Ο~0~ βvalues are 3.1 Γ 10^β13^ s and 3.9 Γ 10^β18^ s.