Iso-conversional and Isokinetic Methods of Analysis of Non-isothermal Crystallization in Ti 50 Cu 20 Ni 30 Metallic Glass Heena Dhurandhar 1,a ,T. Lilly Shanker Rao 2 , Kirit N. Lad 3, b and Arun Pratap 3,c 1 Dept. of Electronics, Mukesh Patel School of Technology Management & Engineering, SVKM’s NMIMS deemed University, Vile Parle West, Mumbai – 400 056, India 2 Electronics Department, Narmada College of Science & Commerce, Zadeshwar, Bharuch – 392011, India 3 Condensed Matter Physics Laboratory, Applied Physics Department, Faculty of Technology and Engineering, The M. S. University of Baroda, Vadodara – 390 001, India a heena0609@yahoo.co.in, b kiritlad@yahoo.com, c apratapmsu@yahoo.com Key words: crystallization, isoconversional, activation energy, metallic glasses. Abstract. The crystallization kinetics of metallic glass Ti 50 Cu 20 Ni 30 has been studied using Differential Scanning Calorimetry (DSC). The DSC thermograms have been analysed using the model-free isoconversional methods and model dependent isokinetic methods. The activation energy(E) for the crystallization process has been determined utilizing; (i) various linear integral isoconversional methods, namely, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose, Li Tang method (ii) linear differential isoconversional method and (iii) different isokinetic methods. In the present work, we intend to the determination of true value of E. The above methods are found to give consistent results for E. Introduction Due to non-crystalline and random atomic arrangement, the metallic glasses exhibit unusual mechanical, magnetic, physical and noncorrosive properties which make them superior to their crystalline counterparts. On the other hand, the metastable nature of amorphous phase is a disadvantage also owing to thermally activated transformation to a crystalline state. For technological applications, such metallic glasses should be thermally stable over a wide range of temperature and time. So, it is important to know the kinetic parameters of crystallization to harness the technological advantages and for controlling the fabrication process. Thermoanalytical techniques like differential thermal analysis (DTA) and DSC are used most often to study the phase transformations. DSC or DTA experiments can be carried out in two modes; (i) isothermal and, (ii) non-isothermal. The choice of the mode to study the kinetics of the phase transformation has always been a matter of debate due to their promising advantages and the inherent limitations. Though the isothermal techniques are definitive in most cases, the non-isothermal techniques possess several advantages over it. The notable features of the non-isothermal techniques are: (i) the rapidity with which the experiment can be performed, (ii) extended temperature range of measurements beyond that accessible to isothermal experiments. Further, many phase transformations occur too rapidly to be measured under isothermal conditions because of transients inherently associated with the experimental apparatus [1]. Non-isothermal transformation kinetics becomes important in such instances. Another important issue, apart from the choice of the experimental mode, is the utilization of a sound method for analysis of the experimental data. Most of the methods, developed to study the phase transformations involving nucleation and growth in metallic glasses, are based on the Johnson-Mehl-Avrami-Kolmogorov (JMAK) transformation rate equation. The JMAK equation is essentially derived on the basis of experiments carried out under isothermal conditions. Nevertheless, it can also be extended to non-isothermal experiments under certain conditions [2, 3]. Solid State Phenomena Vol. 171 (2011) pp 107-119 Online available since 2011/May/17 at www.scientific.net © (2011) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/SSP.171.107 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: 117.254.19.10-26/06/11,14:12:38)