Structure, magnetism, and magnetostrictive properties of mechanically alloyed Fe81Ga19

Abstract

In this work, structure-magnetic property correlations and the magnetostrictive response of mechanically alloyed powders of composition Fe 81 Ga 19 were investigated using a variety of structural and magnetic probes. X-ray diffraction analysis of the as-milled powders suggests the presence of a chemicallydisordered body-centered cubic phase. Thermal annealing of powder compacts results in formation of a secondary phase that demonstrates the cubic ordered L1 2 crystal structure. Magnetostriction measurements indicate that the magnetoelastic properties of the polycrystalline Fe 81 Ga 19 compacts can be tailored by increasing the milling time duration followed by an anneal of the as-milled powders at 900°C for 2 hours in an Ar gas environment (O 2 <5 ppm). Under those conditions, the room temperature saturation magnetostriction was measured to be as high as 41 ppm at a low magnetic field of H app ~10 Oe. The magnetostrictive behavior of the mechanically alloyed Fe 81 Ga 19 powders was found to be comparable with FeGa samples prepared by other non-equilibrium powder processing techniques. Based upon the results presented here, it is proferred that ball-milling offers a cost-effective pathway towards realizing large volumes of FeGa alloys having moderate values of magnetostriction.

Improved magnetostriction in Galfenol alloys by aligning crystal growth direction along easy magnetization axis

“…The composition x = 0.8 shows the highest magnetostriction of 103 ppm for as-cast sample and 188 ppm for DS-treated sample. It should be noted that as for the trace-amount element doped FeGa polycrystalline alloys without treatment of magnetic annealing and prestress during measurement, the reported maximum value of magnetostriction (even DS-treated FeGa alloys) is 160 ppm [29][30][31][32][33][34] . Meanwhile, the Pt doping causes a higher magnetostriction without increasing the saturation field, which can be quantified as dλ/dH, as shown in Fig.…”

Effect of Notches on Magnetic Induction Variation for Magnetostrictive Clad Plate

“…In this case, there is a bias magnetic field along the length direction (easy axis), and the longitudinal (33) magnetostrictive deformation is dominant. Thus, the constants 15 d′ , 31 d′ , and 33 d′ can be given by The basic equations for the magnetostrictive materials are mathematically equivalent to those for piezoelectric materials. Thus, the commercial package ANSYS with coupled-field solid, acoustic fluid, and infinite acoustic elements was used in the simulation.…”

“…(14) However, most works have focused on the improvement of material properties through some subsequent processing techniques, considering the relatively low magnetostriction for most metallic alloys. (15,16) Therefore, the processing procedure has some restriction requirements regarding the equipment employed, and in this case, increasing cost and sophisticated processing are inevitable.…”

Giant Enhancement of Magnetostrictive Response in Directionally-Solidified Fe83Ga17Erx Compounds

“…Further, a B2 ordered cubic phase variant is also noted at high temperatures for compositions exceeding 32 at.% Ga [10]. Depending upon the sample synthesis and the processing technique employed, significant amounts of Ga (well in excess of the solubility limit) can be retained in a metastable disordered bcc solid solution at room temperature [8,10,12]. High magnetostriction values ranging from 250 to 400 ppm have been reported in single crystals of bcc alloys of Fe 1− x Ga x , , where x ranges from 15 to 25 [13].…”