Burgers vector: Shortest lattice translation

Burgers vector: Shortest lattice translation

[@anilkumarmourya6921]

Clear Understanding. Thank you sir.

[@Lamb-In-Our-Flow]

Thank you, sir, for your videos :)

[@jessicapatel4308]

How do we find the same for the zinc blende structure?

[@vipinv5962]

Thank you for the wonderful explanation. Can you please explain the slip planes in BCC and FCC cubic structures

[@introductiontomaterialsscience]

Please look at kzbin.info/www/bejne/m3auYaaQj8qWfLM for slip planes. All videos on Materials Science are organised topic-wise in the following playlist: kzbin.info/door/RFAeCBIRZrY8YcuLomFU1gplaylists

[@vipinv5962]

@@introductiontomaterialsscience Thank you so much

[@tahakhalid324]

I have a question. How do you connect miller indeces of a crystal with burgers vector. Like how they link each other?

[@rajeshprasad101]

Burger's vector has length and direction. So they can be represented by symbols looking like Miller indices. But there is a slight difference. In Miller indices of direction, we are not concerned by the length of the representative vector but the entire line. But in the case of Burger's vector length is also important.

[@vikashlamba9121]

Sir, why can't we write the miller indices of the center of body diagonal in BCC crystal [222] ? or family of ?

[@introductiontomaterialsscience]

As a vector [111] represents the length and the direction of the body diagonal of the unit cell. Thus [222] is a vector twice the length of a body diagonal. If you wish to go from the corner to the centre of the unit cell, i.e., half the length of the body diagonal then it is [1/2 1/2 1/2] or 1/2[1 1 1]. This is one of the possible Burgers vector of the BCC crystal. All possible Burgers vectors of BCC can then be written as 1/2.

[@vikaskumarkushwaha5599]

Great lecture sir

[@narendrakumarchadalavada8553]

Sir Pleade also say Burger vector for HCP structure

[@manoranjankumar5851]

Sir ....nacl is also ionic compound so why it form fcc structure and cscl simple cubic??cscl should also be considered as bcc

[@rajeshprasad101]

For any lattice, all lattice points should have identical surrounding. Thus identical atoms should sit at the lattice points. In particular case of BCC, both corners and the body centre are lattice points. So they should have the same kind of atoms. This is not true in CsCl. So it cannot be considered BCC. You may like to look at this article: link.springer.com/article/10.1007/s12045-016-0346-0

[@ayush7805]

in NaCl , Cl- forms FCC lattice points and Na in the oh voids , but in CsCl , CL- forms simple cubic lattice points and not BCC lattice points , hope it clears your doubt

[@sarveshbhushanvartak2023]

@@ayush7805 Actually in CsCl there is SCC lattice with motif as 2 atoms Lattice = SIMPLE CUBIC Motif/ Basis ={ Cl 000 + { Cs 1/2 1/2 1/2

[@adarshraj_7903]

sir in BCC the shortest distance is between atom at corner and at body center so how it will be 1/2 please explain me sir

[@introductiontomaterialsscience]

From the corner to the body cenre is half the length of the body diagonal 1/2.

[@missionbeingmech9550]

thanx sir.

[@ankitk49]

Sir can we say that Bergers vector is actually for the lattice even when we are considering crystal structures?

[@rajeshprasadlectures]

Burgers vector of a 'perfect' dislocation is always the shortest lattice translation of the lattice of the crystal. The Burgers vector of 'partial' dislocation (not discussed in this course) is not a lattice translation and depends upon the crystal structure.

[@ankitk49]

@@rajeshprasadlectures Thank you sir for the explanation.

[@ankitk49]

@@rajeshprasadlectures Is the difference between perfect and partial dislocation similar to pure and combined streeses in Strength of materials? That we want to deal with them separately before we deal with them together?

[@monishreddy1797]

8:35 sir " b " need not be smallest lattice translation it can be the integer multiple of lattice translation..right?

[@introductiontomaterialsscience]

As the length b of the Burgers vector increases the strain energy of the dislocation increases by b^2. So energetically small Burgers vectors are preferred. In monatomic BCC crystal one sometimes observes a as Burgers vector which is slightly longer than the shortest translation vector a/2.

[@monishreddy1797]

@@introductiontomaterialsscience Thank you sir

[@yelsinmendezcamacho8483]

Pro Rajesh. Thank you for the video. I have one question. Why the burgers vector should be as short as possible?

[@introductiontomaterialsscience]

At 7:35 I explain this terms of minimization of energy of the dislocation.

[@narendrakumarchadalavada8553]

@@introductiontomaterialssciencesir you just said energy should be minimum and my doubt is that why should energy be minimum?

[@arvindpokhriyal5528]

@@narendrakumarchadalavada8553 for gaining stability

[@srbiswal1786]

@@narendrakumarchadalavada8553 for equilibrium