Microstructure characterisation of directionally solidified MnNi damping alloy under strong magnetic field

Abstract

In order to reveal the effect of the magnetic field on the microstructure and the martensitic transformation of directional solidified MnNi alloy, four specimens were prepared by applying different magnetic fields during the directional solidification. The results show that the external magnetic field induces the formation of α-Mn phase, changes the orientations of dendrites as well as increases the dislocation density. The external magnetic field eliminates the fco→fct2 phase transformation and retains the fct→fcc transformation, meanwhile has little effect on the antiferromagnetic transition. The internal friction from twin boundary and phase transformation of directionally solidified MnNi alloy is 3–4 times that of as-rolled MnNi alloy, showing excellent high damping capacity in a wide temperature range.

KEYWORDS:

• MnNi alloy
• strong static magnetic field
• microstructure
• phase transformation

Disclosure statement

No potential conflict of interest was reported by the authors.

Author Contributions

For research articles with several authors, a short paragraph specifying their individual contributions must be provided. The following statements should be used ‘Conceptualization, Q.Tian; methodology, Q.Tian,, Z.Ren.; validation,D.Wang., X.Liu andQ.Tian; formal analysis, D.Wang., X.Liu andQ.Tian; investigation,J.Pu; D.Wang., X.Liu; data curation, J.Pu; D.Wang., X.Liu.; writing—original draft preparation, D.Wang; writing—review and editing, X.Liu; D.Wang ; Q. Tian; visualization, X.Liu; D.Wang.,, Q. Tian; supervision, Q Tian; project administration, Q.Tian; funding acquisition, Q.Tian. All authors have read and agreed to the published version of the manuscript.’ Please turn to the CRediT taxonomy for the term explanation. Authorship must be limited to those who have contributed substantially to the work reported.

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