Lattice expansion and phase stability in nanocrystalline titanium thin films. (3rd August 2021)

• Record Type: Journal Article
• Authors: Chakraborty, J.
• Is Part Of: Philosophical magazine letters. Volume 101:Number 8(2021)
• Page Start: 330
• Page End: 340
• Publication Date: 2021-08-03
• Subjects: Lattice expansion -- phase transformation -- titanium -- crystallites -- hcp -- fcc -- X-ray diffraction; Condensed matter -- Periodicals; Physics -- Periodicals; Solid state physics -- Periodicals; Physique -- Périodiques; 530.41
• DOI: 10.1080/09500839.2021.1937367
• Languages: English
• ISSNs: 0950-0839

Abstract

ABSTRACT: Crystallite-size-dependent lattice expansion of the hcp Ti phase has been observed by X-ray diffraction of polycrystalline Ti thin films. X-ray line profile analysis (XLPA) revealed a systematic reduction of crystallite size in the hcp Ti phase with decreasing film thickness. Increase of specific volume (i.e. volume/atom) of the hcp Ti phase with decreasing crystallite size has confirmed such lattice expansion. The observed lattice expansion has been simulated using an existing theoretical model after appropriately incorporating a crystallite-size-dependent width of the grain boundaries. It is further revealed that decreasing crystallite size and accompanying lattice expansion leads to lattice instability of the hcp Ti phase and eventually to a hcp-fcc phase transformation of elemental Ti in these thin films as reported earlier by the author.