Please, Can any one inform me if XRD can detect the different types of the crystalline imperfections ? What are the used software programs? are there free programs can determine these defects?
If these imperfections are: Point defects (Vacancy defects , Interstitial defects, Stone–Wales defect, ...), Line defects (Dislocations), Planar defects (Grain boundaries, Stacking faults, twin boundary) and the three-dimensional macroscopic or bulk defects, such as pores, cracks, or inclusions.
Dear Ahmed Saeed Hassanien:
The defects that influence the lattice parameters such as interstitials and vacancies or the stacking order such as stacking faults can be detected by XRD. In the former case, you will see shift of reflections to the small angle (if the lattice constants increase) or to large angle (if the lattice constants decrease); in the later case, you will the broaden of the peaks on some crystal planes if there is high density of stacking faults.
Dear Ahmed Saeed Hassanien,
As far as I can see: XRD reveals lineshifts and linebroadening, nothing more and nothing less. Examples of the analysis of lattice-parameter variations, including the analysis of the obtained peaks can be found in my thesis (see attached link). That XRD would detect analytically the full range of crystalline defects as mentioned by your question seems to me an exaggerated expectation: most of the mentioned defects will contribute to lineshift and/or linebroadening.So, unraveling these effects seems me very difficult.
https://www.researchgate.net/profile/P_Mourik/publications?pubType=thesis
Dear Prof.P. Van Mourik
Really, unraveling these effects seems difficult. But, aren't there software programs or any other tools or techniques can analyze and appoint these crystalline defects.
Thanks
Hi,
Point defects (Vacancy defects , Interstitial defects, Stone–Wales defect, ...),
- these are thought not to cause broadening but influence the level of background of a diffraction pattern- this is found in Krivoglaz, M. A. (1996). X-ray and Neutron Diffraction in Nonideal Crystals. Berlin: Springer-Verlag.
Line defects (Dislocations),
- peak profile works better
Planar defects (Grain boundaries, Stacking faults, twin boundary)
- according to Warren (Warren, B. E. (1959). X-ray studies of deformed metals. Progress in Metal Physics, 8(3), 147–202. http://doi.org/10.1016/0502-8205(59)90015-2) planar faults increase broadening in a similar way to crystal broadening (i.e. not dependent on 1/d) but by different amounts for different peaks and also add some assymetry. For twins one must be careful of any inter-granular strain differences. Grain boundaries are in theory given by peak profile methods, but in practicality if dislocations are present too this separation can be difficult.
and the three-dimensional macroscopic or bulk defects, such as pores, cracks, or inclusions.
- for this you need a different type of x-ray: x-ray tomography or similar (i.e. variations in density through a sample). Or if small small angle scattering can be used (i.e. less than about 300 nm) using sasView
For the dislocations part we are putting together our code DPPA for peak profile analysis. See attached for literature and results for plastically deformed metals
Thesis THE USE OF DIFFRACTION PEAK PROFILE ANALYSIS IN STUDYING THE...
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