Galfenol (Fe-Ga alloy) wire fabrication provides a low cost alternative to directional solidification methods. This work evaluates the compositional dependence of the wire drawing suitability of Fe-Ga and characterizes the microstructural and magnetic properties of these wires. Wire has been produced with Ga contents between 10 at. % and 17 at. % to allow determination of the ductile to brittle transition (DTBT) in wire manufacture. Published results on chill cast bend specimens indicated that a DTBT occurs at roughly 15 at. % Ga. This DTBT was observed under tensile loading with a corresponding change in fracture behavior from transverse fracture to intergranular fracture. For improved magnetostrictive performance, higher Ga contents are desired, closer to the 17 at. % Ga evaluated in this work. Electron backscattered diffraction B-H loop and resonance measurements as a function of magnetic field (to determine modulus and coupling factor) are presented for as-drawn, furnace, and direct current (DC) annealed wire. Galfenol wire produced via traditional drawing methods is found to have a strong 〈110〉 (α) texture parallel to the drawing direction. As-drawn wire was observed to have a lower magnetic permeability and larger hysteresis than DC annealed wire. This is attributed to the presence of a large volume of crystalline defects; such as vacancies and dislocations.
11.The MUD (multiples of uniform distribution) is a contouring level referencing a perfectly uniform distribution of the total number of poles/directions throughout a pole figure (MUD level of 1). The higher the MUD, the more clustered the poles/directions and therefore the stronger the texture.
12.Unpublished data for directionally solidified FexGa1−x alloys where 12.5 < x < 35. B data extrapolated to determine 10 at% values. Work completed by ETREMA Products, Inc., under ONR Contract No. N00014-99-C-0053.