Magnetic field-induced reversible variant rearrangement in Fe–Pd single crystals

Variant rearrangements induced by external magnetic field in Fe–Pd FCT martensite transformed from FCC austenite single crystals have been investigated by means of optical microscopy. Fe–Pd single crystals in fully martensite state contain two large correspondence variants, and a kink due to {1 0 1} twinning is observed at the twinning boundary of the variants. The twinning boundary exhibits both large reversible and small irreversible movement by applying magnetic field as a result of variant rearrangement, and 0.49% of reversible strain is obtained. The variant rearrangement is not completed even though magnetic flux density is increased to maximum of an electromagnet used. The boundary also moves reversibly by application of external compression stress, however, the direction of the boundary movement is opposite with respect to the movement induced by magnetic field and the variant rearrangment is not completed. The reversible strain of 2.8% was also observed when the specimen was compressed.