An X-ray diffraction study of nanocrystalline titanium prepared by high-energy vibrational ball milling

• Published in: Applied surface science Vol. 182; no. 3; pp. 372 - 376
• Main Authors: Chatterjee, Partha, Sen Gupta, S.P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 22-10-2001; Elsevier Science
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.); Dislocation; Exact sciences and technology; Materials science; Nanocrystal; Nanoscale materials and structures: fabrication and characterization; Physics; Structure of solids and liquids; crystallography; X-ray diffraction; X-ray diffraction; Nanocrystal; Dislocation; Dislocation density; Crystal defects; Transition elements; Dislocation structure; Titanium; XRD; Experimental study; Lattice parameters
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(01)00451-2

A detailed X-ray line-broadening study in ball-milled Ti sample is presented. It is observed that ball milling leads to the formation of nanocrystalline grains and transform partially to an f.c.c. Ti-phase after 10
h of milling. Using a Rietveld analysis, the volume fraction of f.c.c. phase was found to be ∼24% with a crystallite size of ∼20
Å. The origin of high strains is probably the dislocations present in the sample. Anisotropic line broadening of the fault-unaffected reflections is explained in terms of anisotropic dislocation contrast corresponding to 〈
a〉 and 〈
a+
c〉 dislocations. Both edge and screw dislocations were predicted with a significant basal slip. High dislocation density ∼10
11
cm/cm
3 has been found in the milled samples. A large increase in the isotropic thermal parameter was also observed for the h.c.p. Ti-phase after 10
h of milling.