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Journal of Nanomaterials
Volume 2018, Article ID 2560641, 11 pages
https://doi.org/10.1155/2018/2560641
Research Article

Influence of Milling Time on Structural and Microstructural Parameters of Ni50Ti50 Prepared by Mechanical Alloying Using Rietveld Analysis

1Laboratoire de Physique des Solides, Department of Physics, Faculty of Science, University Badji Mokhtar, Annaba, Algeria
2Laboratoire d’Elaboration et d’Analyse des Materiaux LEAM, Department of Physics, Faculty of Science, University Badji Mokhtar, Annaba, Algeria
3Laboratoire de Microstructures et Defauts, Department of Physics, Faculty of Science, University of Mentouri, Constantine, Algeria
4Department of Physics, College of Science, University of Bahrain, P.O. Box 32038, Manama, Bahrain

Correspondence should be addressed to E. Sakher; gro.abanna-vinu@rehkas.mehafle

Received 16 September 2017; Accepted 5 December 2017; Published 14 January 2018

Academic Editor: Leszek A. Dobrzański

Copyright © 2018 E. Sakher et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nanostructured Ni50Ti50 powders were prepared by mechanical alloying from elemental Ni and Ti micrometer-sized powders, using a planetary ball mill type Fritsch Pulverisette 7. In this study, the effect of milling time on the evolution of structural and microstructural parameters is investigated. Through Rietveld refinements of X-ray diffraction patterns, phase composition and structural/microstructural parameters such as lattice parameters, average crystallite size , microstrain , and stacking faults probability (SFP) in the frame of MAUD software have been obtained. For prolonged milling time, a mixture of amorphous phase, NiTi-martensite (B19′), and NiTi-austenite (B2) phases, in addition to FCC-Ni(Ti) and HCP-Ti(Ni) solid solutions, is formed. The crystallite size decreases to the nanometer scale while the internal strain increases. It is observed that, for longer milling time, plastic deformations introduce a large amount of stacking faults in HCP-Ti(Ni) rather than in FCC-Ni(Ti), which are mainly responsible for the observed large amount of the amorphous phase.