Materials Science Forum Vols. 738-739 (2013) pp 274-275 Online available since 2013/Jan/25 at www.scientific.net © (2013) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/MSF.738-739.274 STRAIN GLASS REVISITED a Kustov S., a Salas D., a Cesari E., a Santamarta R., b Mari D., c Van Humbeeck J. a Universitat de les Illes Balears, Palma de Mallorca, Spain b Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland c Katholieke Universiteit Leuven, Leuven, Belgium e-mail: Jan.VanHumbeeck@mtm.kuleuven.be Keywords: strain glass, young’s modulus, internal friction Introduction: According to the most general interpretation, a glassy transition (transition to the glassy state) is a transition between the high temperature “liquid” state in which certain species are disordered due to thermal excitation. This disordered “liquid” state is an equilibrium state and a “glassy” state is the one in which the same species are in a “frozen” disorder, inherited from the high-temperature “liquid” state. This is a kinetically non-equilibrium state, when the equilibrium state cannot be reached due to a divergence of the relaxation time. In the case of the “glassy martensite” concept [1], [2], relevant “species” are not introduced clearly, but, it probably can be understood that these “species” are nanodomains of the R phase-like structure. Such domains were earlier observed and described by Murakami et al. [3]. The disorder in such a system is understood as a random orientation of the transformation strain in these domains, resulting in the absence of macroscopic transformation strain, or the absence of the long-range strain ordering. The term “strain glass” seems to be consistent with this understanding. However, at least two fundamental conditions from the abovementioned definition of the glassy transition are not fulfilled in the case of “glassy martensite” transition. 1) It is not obvious, and, moreover, doubtful, that the same species which are involved in the glassy state do exist on the high-temperature and low-temperature sides of the supposed “glassy” transition. We would expect that these nanodomains of martensite simply do not exist in the high-temperature phase. Even the TEM results in [1] show that actually they appear and grow in the range of the supposed “glassy” transition as also observed in [3]. 2) Even if these nanodomains exist in the high-temperature phase, they are not in thermally produced equilibrium disrordered state. Indeed, the samples with excess of Ni quenched from around 1300 K do possess certain disorder, and, hence, random distribution of certain lattice strains. However, this is the quenched and non-equilibrium disorder, inherited from the high quenching temperature and not the thermally induced equilibrium disorder of the liquid state. Thus, the concept of “glassy martensite” seems to be inconsistent with the fundamentals of the glass transition. To resolve this question, new IF-measurements in a wide frequency domain (10-1 Hz-105 Hz) have been performed. Although some results, including the internal friction data obtained at low frequencies, are partially in agreement with the observations in [1,2], a more detailed analysis of the new data shows that anelatic phenomena, attributed previously to the “glass transition”, should be interpreted as an anelastic relaxation superimposed with a partial and diffuse martensitic transformation. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 128.178.178.136, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland-23/03/15,14:56:00) Materials Science Forum Vols. 738-739 An initial description an interpretation of those results will be presented during this conference. A more extended and detailed analysis will be published in the near future. References [1] S. Sarkar, X. Ren, K. Otsuka, Phys. Rev. Letters, 95, 205702 (2005). [2] Yu Wang, X. Ren, K. Otsuka, Phys. Rev. Letters, 97, 220703(2006) [3] Y. Murakami, D. Shindo., Phil Mag Lett 2001;81:631 275 European Symposium on Martensitic Transformations 10.4028/www.scientific.net/MSF.738-739 Strain-Glass Revisited 10.4028/www.scientific.net/MSF.738-739.274 DOI References [1] S. Sarkar, X. Ren, K. Otsuka, Phys. Rev. Letters, 95, 205702 (2005). http://dx.doi.org/10.1103/PhysRevLett.95.205702