Avalanche criticality in thermal-driven martensitic transitions: the asymmetry of the forward and reverse transitions in shape-memory materials*This paper is dedicated to our friend Ekhard Salje in the occasion of his 70th birthday. (21st July 2017)

• Record Type: Journal Article
• Authors: Planes, Antoni; Vives, Eduard
• Is Part Of: Journal of physics. Volume 29:Number 33(2017)
• Publication Date: 2017-07-21
• Subjects: avalanche criticality -- martensitic transition -- acoustic emission -- Cu–Zn–Al -- Fe–Pd; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa78d7
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Martensitic transitions take place intermittently as a sequence of avalanches which are accompanied by the emission of acoustic waves. The study of this acoustic emission (AE) reveals the scale-free nature of the avalanches. In a number of shape memory materials undergoing a martensitic transition it has been found that, in spite of relatively low hysteresis, the dynamics of forward and reverse transitions are different, which may explain the fact that the AE activity is different in both forward and reverse transitions. The asymmetry could be a consequence of the fact that, while nucleation is required for the transition from the parent to martensitic phase to take place, reverse transition occurs by fast shrinkage of martensitic domains. We have analysed in detail the distribution of avalanches in cooling and heating runs in Fe–Pd and Cu–Zn–Al shape-memory alloys. In the former, the martensitic transition is weakly first order while it shows a significant first order character in the latter. We have found that in Fe–Pd the distributions are power law for the forward and reverse transitions characterized by the same critical exponents. For Cu–Zn–Al the distribution of avalanches is critical in forward transitions but exponentially damped in the reverse transition. It is suggested that this different behaviour could originate from the different dynamic mechanisms in forward and reverse transitions.