Anelasticity of Phase Transitions and Magnetostriction in Fe-(27-28%)Ga Alloys

Abstract

Several aspects of anelastic behavior of Fe-(27-28%)Ga-Tb alloys are considered in this paper: (i) the phase transitions from a metastable to an equilibrium phase and phase transitions between equilibrium phases at higher temperatures in as cast alloys, (ii) the nature of corresponding three transient anelastic effects, (iii) the formation of an intrinsic composite microstructure with a different ratio between the bcc-derivative metastable and fcc-derivative equilibrium phases that have different magnetostriction and the effect of alloys doping by Tb to stabilize the metastable phase with high positive values of magnetostriction.

Anelastic Effects in Fe–Ga and Fe–Ga-Based Alloys: A Review

“…Activation parameters (τ 06 ≈ 2 × 10 −16 s and H 6 = 2.7 eV) suggest a grain boundary mechanism of this peak. Later, a similar peak was reported for Fe–27Ga (2.8 eV) [ 46 , 47 ], and, most recently, the interpretation of this effect as a grain boundary peak was confirmed for Fe–30Ga alloy with activation parameters: τ 0 ≈ 10 −12 s and H ≈ 2.1 eV [ 61 ].…”

“…Analysis of TDIF spectra for a wide range of Ga concentration was done in several papers by Golovin et al for 8–33%Ga [ 11 , 49 ], for 19, 27, and 28%Ga [ 47 , 50 ], and for 23–38%Ga [ 60 ]. The important feature of most of these studies is the parallel real-time internal friction and neutron diffraction studies using the same materials with the same heating and cooling rates.…”

“…At higher temperatures (up to ~800 °C), 2 more transient effects were reported using forced inverted torsion pendulum at EPFL [ 46 , 50 ]. A typical example of several phase transitions in as-cast (or air- or water-quenched) Fe 3 Ga-type alloy is shown in Figure 21 [ 11 , 46 , 47 , 50 ]. Three first-order phase transitions (D0 3 → L1 2 → D0 19 → B2) in Fe–(27–28)Ga compositions are accompanied with three transient effects, namely: P Tr1 (D0 3 → L1 2 ), P Tr2 (L1 2 → D0 19 ), and P Tr3 (D0 19 → B2) [ 46 , 47 , 50 ].…”

“…A typical example of several phase transitions in as-cast (or air- or water-quenched) Fe 3 Ga-type alloy is shown in Figure 21 [ 11 , 46 , 47 , 50 ]. Three first-order phase transitions (D0 3 → L1 2 → D0 19 → B2) in Fe–(27–28)Ga compositions are accompanied with three transient effects, namely: P Tr1 (D0 3 → L1 2 ), P Tr2 (L1 2 → D0 19 ), and P Tr3 (D0 19 → B2) [ 46 , 47 , 50 ]. At this point, researchers should not mix up the P Tr1 and P Tr2 peaks ( Figure 21 ) for Fe–27%Ga with similarly abbreviated peaks in Figure 6 , Figure 7 , Figure 8 , Figure 9 and Figure 10 : they have different natures, discussed in detail in Section 3.1 and Section 3.2 , correspondingly.…”

“…Our studies of thermally activated (Snoek and Zener relaxations), transient (due to A2 ↔ D0 3 , D0 3 → L1 2 , L1 2 → D0 19 , D0 19 → B2 phase transitions), and amplitude-dependent (damping) effects in Fe–Ga alloys were strengthened by cooperation with colleagues from China, Spain, Switzerland, Taiwan, and the US. Studies of phase transitions were supported by parallel real-time neutron diffraction measurements at JINR, Dubna [ 24 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. A review of frequency- and temperature-dependent anelastic effects in Fe–Ga alloys was presented by the author of this paper at the 18th International Conference on Internal Friction and Mechanical Spectroscopy (ICIFMS-18, Brazil, 2018).…”