Shape memory behavior in Fe₃Al-modeling and experiments

Abstract

The Fe₃Al alloy with D0₃ structure exhibits large recoverable strains due to reversible slips. Tension and compression experiments were conducted on single crystals of Fe₃Al, and the onset of slip in forward and reverse directions were obtained utilizing high-resolution digital image correlation technique. The back stress provides the driving force for reversal of deformation upon unloading, resulting in a superelastic phenomenon as in shape memory alloys. Using density functional theory simulations, we obtain the energy barriers (GSFE – generalized stacking fault energy) for {1 1 0}〈1 1 1〉 and {1 1 2}〈1 1 1〉 slips in D0₃ Fe₃Al and the elastic moduli tensor, and undertake anisotropic continuum calculations to obtain the back stress and the frictional stress responsible for reversible slip. We compare the theoretically obtained slip stress magnitudes (friction and back stress) with the experimental measurements disclosing excellent agreement.

Keywords:

• shape memory
• pseudoelasticity
• recoverable strain
• reversible slip
• digital image correlation
• density functional theory

Acknowledgements

The work was supported by the National Science Foundation, NSF CMMI-1300284. This support is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the National Science Foundation [NSF CMMI-1300284]; Division of Civil, Mechanical and Manufacturing Innovation [grant number 1300284].