A1 Journal article (refereed), original research

Transitory Ultrasonic Absorption in “Domain Engineered” Structures of 10M Ni-Mn-Ga Martensite


Open Access publication


Publication Details

Authors: Kustov Sergey, Saren Andrey, D’Agosto Bruno, Sapozhnikov Konstantin, Nikolaev Vladimir, Ullakko Kari

Publisher: MDPI

Publication year: 2021

Language: English

Related journal or series: Metals

Volume number: 11

Issue number: 10

eISSN: 2075-4701

JUFO level of this publication: 1

Digital Object Identifier (DOI): http://dx.doi.org/10.3390/met11101505

Open Access: Open Access publication


Abstract

In this work we create in 10 M Ni-Mn-Ga martensitic samples special martensitic variant structures consisting of only three twins separated by two a/c twin boundaries: Type I and Type II, with relatively low and very high mobility, respectively. The “domain engineered” structure thus created allows us to investigate the dynamics of a single highly mobile a/c twin boundary (TB). We show that temperature variations between 290 and 173 K in our samples induce an intense transitory internal friction at ultrasonic frequencies ca. 100 kHz, peaking around 215 K. A comparison is made of the data for the “domain engineered” sample with the behaviour of reference samples without a/c TB. Reference samples have two different orientations of a/b twins providing zero and maximum shear stresses in a/b twinning planes. We argue, first, that the transitory internal friction, registered at rather high ultrasonic frequencies, has magnetic origin. It is related with the rearrangement of
magnetic domain structure due to the motion of a/c twin boundary induced by thermal stresses. This internal friction term can be coined “magnetic transitory internal friction”. Magnetic transitory internal friction is a new category, linking the classes of transitory and magnetomechanical internal friction. Second, the structure of a/b twins is strongly non-equilibrium over a broad temperature range. As a consequence, the Young’s modulus values of the samples with maximum shear stress in a/b twinning planes can take any value between ca. 15 and 35 GPa, depending on the prehistory of the sample.


Last updated on 2021-28-09 at 10:04