Phase Stability of Three Fe–Mn–Al–Ni Superelastic Alloys with Different Al:Ni Ratios

VALLEJOS, J. M.; GIORDANA, M. F.; SOBRERO, C. E.; MALARRIA, J. A.

Shape Memory and Superelasticity

Springer Nature

Año: 2021 vol. 7 p. 362 - 372

2199-384X

Fe?Mn?Al?Ni superelastic alloy is a potentialcandidate for diverse engineering applications due to its outstandingproperties and low material costs. Recent studies suggest that slight changesin the chemical composition severely affect superelastic response, phasestability and grain growth kinetics. In this paper, we found that the Alstabilizes the parent α phase at high temperature and promotes the formation ofβ precipitation at lower temperature. An alloy with a 3:1 ratio between Al andNi produces homogeneously distributed β precipitates with high phase fractionin the alpha matrix after quenching from 1200 °C. The presence of theseprecipitates stabilizes the α phase, lowers the martensitic transformationtemperature and gives the alloy a fully-reversible stress-induced martensitictransformation behaviour without the need to apply an aging step. In alloyswith lower Al content the β precipitation produced during quenching is severelyrestricted and pseudoelasticity is impaired.