Stress annealing of Fe–Ga transduction alloys for operation under tension and compression

The addition of Ga to bcc α-Fe increases the magnetostriction of Fe in the [100] direction (a factor of 12 for Fe81Ga19). The effect of annealing highly textured polycrystalline Fe81.6Ga18.4 rods under compressive stresses of −100 and −150MPa for 10–100min at temperatures between 625°C and 635°C was examined. After annealing, all samples showed nearly full performance at near-zero stresses. Samples annealed with −100MPa stress maintained a high magnetostriction up to ∼20MPa tensile stress; the sample annealed with −150MPa stress maintained its magnetostriction up to ∼30MPa.