The coupling between first-order martensitic transformation and second-order antiferromagnetic transition in Mn-rich γ-MnFe alloy

Abstract

The fcc → fct martensitic transformation of a Mn-rich γ-MnFe alloy with a (011) martensite twin was investigated using transmission electron microscopy, dynamic mechanical analysis, electrical resistance measurements, differential scanning calorimetry and dilatometry. Experimental results show that the start temperature (M _s) of the martensitic transformation and the temperature (T _N) of the antiferromagnetic transition in Mn_85.5Fe_9.5Cu₅ alloys are close and almost coincide. Direct and reverse martensitic transformations, normally a first-order transformation, exhibit features similar to those of a second-order continuous transition, which is attributed to coupling between the first-order martensitic transformation and the second-order antiferromagnetic transition.

Keywords:

• transformation coupling
• first-order martensitic transformation
• second-order antiferromagnetic transition
• γ-MnFe alloy
• characterization

Acknowledgement

The present work is supported by the National Natural Foundation of China (Grant No. 50571065).