Kinetics of the pressure-induced hcp -+ fcc transformation in thallium

Mohan, Murali and Singh, AK (1994) Kinetics of the pressure-induced hcp -+ fcc transformation in thallium. In: Proceedings of the National Conference on High Pressure Science and Technology, 10-11 Oct 1994, Bangalore, India.

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Abstract

The progress of the hcp + fcc transformation in T1 has been monitored as a function of time, t, under isobaric-isothermal conditions in the pressure range 3.4 - 4.1 GPa at 300K. The decrease in the electrical resistance of the specimen, associated with the transformation, has been used to obtain the fraction, C, of the fcc phase as a function o f t at desired pressures in the above range. The results indicate that (i) the time for C = 0.9 decreases from -105s at 3.4 GPa to wlOs at 4.1 GPa (ii) the activation free energy for the total process decreases from N 14 kcal mol-' at 3.5 GPa to -10.5 kcal mol-' at 413; GPa (iii) the activation volume in the 3.4 - 4.1 GPa range is -30.5 cm3 mol-'.Contrary to our earlier results on the a -+ w transformation in Ti and the fcc -+ bcc transformation in Yb, the hcp -+ fcc transformation in TI does not exhibit an incubation period, and the C-t data do not satisfy the standard form of the Avrami equation.

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: Kinetics;Transformation;Thallium
Subjects: PHYSICS > Physics(General)
Depositing User: Users 90 not found.
Date Deposited: 20 Aug 2008
Last Modified: 17 Jun 2010 08:24
URI: http://nal-ir.nal.res.in/id/eprint/4902

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