Effect of ordering process on giant pseudoelasticity in Fe3Al single crystals Original Research Article

Pseudoelasticity in Fe3Al single crystals with the D03 structure was investigated focusing on the ordering process and the ordered domain structure. During unloading, a plastic strain of 5.0% was perfectly recovered in Fe–23.0at.%Al single crystals with an appropriate heat treatment, while Fe–28.0at.%Al crystals exhibited little strain recovery. The ordered domain structures in slowly cooled Fe–23.0at.%Al and Fe–28.0at.%Al were different from each other depending on their ordering process. In Fe–23.0at.%Al, the strong interaction between specific domain boundaries and superpartial dislocations with Burgers vector of 1/4<1 1 1> led to the individual motion of the superpartials dragging an antiphase boundary (APB). The surface tension due to the APB resulted in the pseudoelasticity in Fe–23.0at.%Al single crystals. In addition, APB created by an intersection between the domain boundaries and the superpartials also pulled back the superpartials during unloading. A refinement of ordered domains was effective in enhancing the pseudoelasticity in Fe3Al crystals.