Screw Dislocations {Texas A&M: Intro to Materials (MSEN 201)}

Short video describing screw dislocations: definition, Burgers vector, stress fields.
Video lecture for Introduction to Materials Science & Engineering (MSEN 201/MEEN 222), Texas A&M University, College Station, TX.
engineering.tamu.edu/materials

[@nurizzateeazlee]

this is really helpful. they should name the vector as shamberger's vector :)

[@mallickrishg]

this is really good. i was wondering why textbooks kept referring to it as a 'screw' dislocation, i really liked the visual explanation of the helical path of the screw. thanks for this. Rishav

[@random3927]

I'm glad there is good people like you in this world. Thank you.

[@tvincentification]

Wow, this really helped explain this. I appreciate you taking the time to record and share this, many thanks.

[@santiagosierra3555]

I FINALLY UNDERSTOOD THIS, THANKS A LOT

[@Kaaukuu]

Like your edge dislocation video, this is a terrific explanation! Thank you very much!

[@deepjyotidas2891]

thank you so much...you explained these concepts so nicely

[@pancakeofdestiny]

This was quite useful. I also find your Texan "howdy" charming

[@ZheShienLim]

Thanks! Finally solved my doubt on what Burgers vector on screw dislocation is like!

[@annezou9059]

THANK YOU SO MUCH I UNDERSTAND NOW! I wish all my professors could explain like you can ^_^

[@manishtiwari2708]

I followed Callister's book but couldn't been able to imagined this way, thank you professor

[@HJeff]

Fantastic video. Excellent job. Thank you so much.

[@elizabethlaskowski8256]

THIS IS SO HELPFUL!! THANK YOU THANK YOU!!!

[@rigzenangmo9732]

thank you so much...this really really helped.. you are an amazing teacher... !!!

[@grandlong5462]

Great explanation. Thank you!

[@STEROIDZZZZZZ]

Great video. Thank you!

[@raphaelmercier4669]

Thanks for this helpful video!

[@Tunquenino]

Thanks for the video! i really liked.

[@imti041413]

helped me a lot..thank you Sir!

[@lufie97]

thank u.. this n edge dislocation was a great help..

[@SaifulIslambangladesh]

Thank you for nice explanation.

[@VKgaming7447]

impeccable explanation...

[@vgpsir]

Really helpful video. Thanks :)

[@noondonporn9710]

Wish my professor teach really well like you

[@adamatir3653]

thank u , a lot :D , i really understood it quickly

[@adruthahr1811]

Really helpful,thanks

[@ruipedro97scp]

Great video explanting Brocolli's vector

[@bilalkarakas7655]

the healthier one indeed

[@DeepakKumar-xf1ll]

Good explanation

[@PabloGonzalezS]

Hello, your explanation is very clear. You said de burger vector goes RH/SF, but that is at the beginning of the dislocation but I still have some doubts. What if we see the figure from the other side, does de burger vector go RH/FS? I don't know if I'm making myself clear. Hope you understand what I mean, english is not my native language. Thanks in advance.

[@shian304]

Thank you!

[@swatantrak2552]

Burgers vector provides us with direction of edge dislocation line. In the end u said with particular direction of shear dislocation motion is perpendicular to bergers vector right...?

[@samahhope7104]

thanks a lot that really helpful thaaaaaaanks ^^

[@mrsush1994]

sir really need help of urs on this statement i have been pondering for long.... and here i quote " climb is a dislocation movement in which dislocation moves from one slip plane to another slip plane ." but when we see in video motion of dislocation is just in the single plane ... please explain

[@zivnawi7941]

thank you vary much!

[@MrSals123]

awesome

[@SIYAK100]

Thanks a lot

[@prasad.vishnu]

Really helpfull...

[@petergriffin6]

thanks a lot

[@deepjyotidas2891]

sir please kindly explain the direction between b vector and dislocation line ( t vector) in -ve screw disloation...

[@niteshstryker]

very clear explanation.could u suggest a good book on material science?

[@pjshamberger]

Nitesh Stryker Thanks! the intro textbook by Callister (there are a couple different versions with different organization of content) has been adopted by an overwhelming fraction of into materials science courses. Not to imply that this is the only one, but I do believe it's clear, and as good as any other intro text out there.

[@strateeg32]

+Patrick Shamberger I have a small question: At minute 2.17, what is the exact location of the dislocation line? Because my book places it just like it is placed in the bottom picture on that minute (so about two interatomic distances away from the start). While in the above picture, in which you draw it, it is placed right at the start of the dislocation. So if you look at the bottom picture, it is placed in the middle row of the green atom dots. While I would have expected the last row of blue atom dots, that is next to the first row of green atom dots. Because from there the dislocation seems to start and get worse when you move to the 'D' in that picture.

[@pjshamberger]

+strateeg32 Good (and subtle) question. The easy answer is that the dislocation must be located entirely within the burger circuit that results in the burgers vector for that dislocation. Certain dislocations can have very tight dislocation cores, so it's easy to localize the dislocation with a very specific position (e.g., screw dislocations in BCC metals. see: the image here: www.mcl.at/en/forschung/atomistic-modeling/dislocation-modeling.html ). In the cartoon drawing in the video, the shear is spread over ~4 or so interatomic distances (i.e., those atoms shown in green), so to get a burger's vector, your burgers circuit must be relatively large to accommodate all of this shear. Thus, it's a little difficult to identify EXACTLY where the dislocation is within that circuit. However, there's another piece of information which wasn't discussed in the video (And perhaps not in your text), which is that shear is distributed radially around a dislocation. That is, there's nothing too special about the step plane that is shown in the image. Thus, the book is correct in locating the dislocation centered in the middle of the region of shear.

[@MarcABOC]

I use Fundamentals of Material Science and Engineering by Callister (4th edition) and it is a great book! Totally would recommend it :)

[@emirhancalim9556]

thank youuu

[@gemacabero6482]

I thought Burguer's vector went in the direction of slip. And that a slip direction is the direction of the movement of the dislocation. However this is not true for screw dislocations. Where am I going wrong? Thanks!

[@nidaaa7714]

thanks

[@TheLizard989]

Do your friends ever call you the shamburgler?

[@costirgot]

ty

[@govindvegisetti548]

good

[@shabbufateh]

is twining and screw dislocation the same

[@atmakuriraviteja8155]

no disslocation is movement of a row of atoms twinning is movement of a whole region of atoms

[@parth9398]

thnx sir

[@andrewciricillo9726]

H O W D D Y D A D DY

[@charlesfu33]

What he teaches is right, but I wonder how he spent so much time to explain so shallow things?

[@georgegithinji935]

Didn't understand you......your diagram is small

[@rigzenangmo9732]

thank you so much...this really really helped.. you are an amazing teacher... !!!

[@hiii5382]

Thank you!