Thickness-dependent fcc-hcp phase transformation in polycrystalline titanium thin films

Chakraborty, J and Kumar, Kishor and Ranjan, Rajeev and Chowdhury, Ghosh S and Singh, SR (2011) Thickness-dependent fcc-hcp phase transformation in polycrystalline titanium thin films. In: Acta Materialia, 59 (7). pp. 2615-2623.

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Abstract

Polycrystalline Ti thin films are shown to gradually transform from face-centered cubic (fcc) to hexagonal close-packed structure (hcp) with increasing film thickness. Diffraction stress analysis revealed that the fcc phase is formed in a highly compressive hcp matrix (>= 2 GPa), the magnitude of which decreases with increasing film thickness. A correlation between stress and crystallographic texture vis-a-vis the fcc-hcp phase transformation has been established. The total free energy change of the system upon phase transformation calculated using the experimental results shows that the fcc-hcp transformation is theoretically possible in the investigated film thickness regime (144-720 nm) and the hcp structure is stable for films thicker than 720 nm, whereas the fcc structure can be stabilized in Ti films much thinner than 144 nm. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	Acta Materialia
Publisher:	Elsevier science
Additional Information:	Copyright of this article belongs to Elsevier science.
Keywords:	X-ray diffraction;Phase transformation;Stress;Texture
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	19 Apr 2011 07:44
Last Modified:	19 Apr 2011 07:44
URI:	http://eprints.iisc.ac.in/id/eprint/36978

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