Magneto-mechanical and damping properties in Fe79.9Al20-xGaxTb0.1 alloys

Large magneto-mechanical properties are attained for Fe79.9Al20-xTb0.1Gax alloys prepared by direc-tional solidification (DS). We obtain high delta E (AE) effect of 9.1-13.4 % and magneto-mechanical coefficient (K) of 29.7-49.5 % with good controllability of E by H and high sensitivity of E at low H, beneficial for the practical applications. The enhanced AE effect and K is sensitive to Ga content mainly due to the increased magnetostriction susceptibility (d lambda///dH). The improved d lambda///dH is contributed from the increased A lambda mainly due to lattice softening with Ga substitution for Al in A2 phase and also magnetic softening, possibly associated with higher (110) texture. The almost linear relationship be-tween AEs/E0 and K2 suggests the experimental AEs/E0 obtained from IEV-RFDA (f similar to 2 kHz) well agrees the theoretical estimated K2 according to the sound propagation theory. Besides, Ga substitution de-creases damping capacity of the alloys Psi(=AW/W), the change of the damping capacity (A Psi) with H, from 3.73 % for x = 0-0.73-1.04 % for x = 5-20. The almost linear relation between the experimental A Psi and theoretically estimated Psi eth reveals the micro eddy-current mechanism dominates the A Psi at 2 kHz. The decreased in A Psi, measured by RFDA with Ga substitution is mainly related to the reduction of the magnetic domain width and the decrease of E0 due to lattice softening. Several anelastic effects are reported for sub-resonance forced vibrations (DMA: 0.1-30 Hz): thermally activated Snoek (P1) and Zener (P2) effects and high damping plateau (background Qb-1) below 200 degrees C even for low strain (5 x10-3 %). Dependence of the background damping level (Qb-1) on ratio Al/Ga is also non-linear with the maximum in ternary compositions Fe-20(Al+Ga).(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study prepared Fe-Al-Tb-Ga alloys through directional solidification method, achieving high magneto-mechanical properties with sensitivity to Ga content and good controllability. Experimental and theoretical studies revealed that magnetostriction susceptibility and damping capacity are influenced by Ga content and lattice softening.