Temperature dependence of pseudoelasticity in Fe3Al single crystals

Pseudoelastic behaviour of D03-ordered Fe–23.0 and 24.7 at% Al single crystals deformed at different temperatures was examined. At room temperature, 1/4〈111〉 superpartial dislocations moved individually dragging the nearest-neighbour antiphase boundaries (NNAPB) during loading. During unloading, the NNAPB pulled back the superpartials resulting in the pseudoelasticity. Fe–23.0Al single crystals showed high recovery ratio in the wide temperature range from 223 to 473 K, while little strain recovery was obtained at the other tested temperatures. Below room temperature, the frictional stress of 1/4[111] superpartials increased with decreasing temperature, which resulted in low recovery ratio. Moreover, the recovery strain at 24.7Al dropped steeply at around 373 K. At 473 K, the quadruplets of 1/4[111] superpartials were observed at 24.7Al. No NNAPB were left behind the quadruplets resulting in little strain recovery at and above 473 K. The change in dislocation configuration was closely related to the ordered domain structure in the D03 phase.