I am working on Ni-Ti thin films and want to calculate the density of dislocation by using Wiilliam Hall formula. For that I required Burger Vector corresponding to (110) plane (BCC).
For the determination of the Burgers vector you need to insert the type of an expected dislocation. Then go around the dislocation core (line) adding the same amount of steps (vector). The missing vector component is the shift caused by the dislocation. That's the Burgers vector.
In fact I can only agree with Wei-Ying Chen, and if somebody distribute negative flags he/she should at least explain why. We are all not perfect and sometimes fail but here I do not see why?
For the determination of the Burgers vector you need to insert the type of an expected dislocation. Then go around the dislocation core (line) adding the same amount of steps (vector). The missing vector component is the shift caused by the dislocation. That's the Burgers vector.
In fact I can only agree with Wei-Ying Chen, and if somebody distribute negative flags he/she should at least explain why. We are all not perfect and sometimes fail but here I do not see why?
Just imagine the bcc lattice and the (110) slip system. The burgers vector b would then be calculated as sqrt(3) times a/2. sqrt(3), because dislocation would slip in this preferred slip system through the crystal. If the slip system changes, the Burger's vector must change too.
Unfortunately, NiTi is not described by the bcc lattice but by a primitive lattice (CsCl structure type). Therefore, a/2 is very likely incorrect.
Dear Veeresh,
In NiTi shape memory alloys the beta phase (high temperature) has indeed a B2 structure, and the burgers vector is b= in the gliding system determined by (110) and the corresponding equivalent symetries.
I send you, here attached, an interesting recent reference from which you may follow other references, particularly ref. 16 and 49. In page 269 of this paper you have a clear indication about your question.
Best regards,
Dear Dr. Veeresh Kumar
Have a nice time and good day
the attached papers may help you.
Good Luck
Thank you for valuable suggestion. Since NiTi alloy is a B2 structure, I follows the Jose San Juan comments.
Dear dr. Veeresh Kumar
Equations no. 15 (Microstrain) and 20 (dislocation density) are always used for semiconductors, Metals or alloys case.
They are valid for all cases.
The attached paper study the microstructure of Al-Mg alloys and uses these equations.
Good Luck
I am very much thankful to all of you for your suggestion and help. I have no words to express my gratitude toward you. Thank you all.
Gert Nolze i am confusing how can i calculate the burger vectors in TEM. Burger vectors are used to calculate the "a" types dislocation , a +c and -a+c types inclined dislocations. First of all i want to know the orientation and directions by pictorial way then i want to know that how they are calculated in TEM and in theory . I am beginners and want to understand a very clear pictures about this topic
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