X-RAY INVESTIGATION OF MECHANICAL MILLING OF Ni3Al (0.2wt%B) POWDER : DISORDERING, CRYSTALLITE REFINEMENT
M. Khitouni*, A. W. Kolsi, N. Njah
Laboratoire de Chimie Inorganique, Faculté des Sciences, B. P.802, 3018 Sfax, Tunisie
* Corresponding author. E-mail :firstname.lastname@example.org
Received : 15 January 2002; revised version accepted : 03 July 2002
We have used the X-ray diffraction analysis to investigate disordering kinetics and nanocrystalline structure formation during filing and mechanical milling in Ni3Al(0.2wt%B) ordered alloy. X-ray reflections were analysed to determine the degree of the long range parameter order, crystallite size and lattice microstrains. A complete disordered structure was induced by filing. Whereas, mechanical milling induces a progressive decrease of the long range order parameter. By using the Langford approach, we have calculated the average of the crystallite size and the lattice strain. The main result is the opposite contributions of the crystallite size and the microstrains. This phenomena was explained by many features should operate simultaneously: the creation of the stacking faults by intensive deformation and the crystallite refinement.
Keywords: X-ray diffraction; Mechanical milling; Disordering; Nanocrystalline Materials.