Thank you so much for the dislocation climb explanation!
@BABBYz5 жыл бұрын
Better than what my professor teaching. Thanks ! you're the best
@anooptiwari40984 жыл бұрын
You are great. I love your way of teaching.
@JobayerJisan2 жыл бұрын
The best teacher in this area
@xPaNzIxKinG5 жыл бұрын
You are fantastic! Thank you!
@shivkumarojha94493 жыл бұрын
Your teaching skills are very good
@nickosborne58223 жыл бұрын
Always clear explanations - thank you very much!
@ducky4185 Жыл бұрын
So damn good
@aravindkumar66314 жыл бұрын
Sir what is pierls strees is it different from crss if it is how
@mussagan4 жыл бұрын
20:20 , shouldn't it become a JOG as remaining dislocation ( into the plane of the screen will still keep lying in the same plane )?
@introductiontomaterialsscience4 жыл бұрын
You are right. The single stem shown here will create a jog. For the entire dislocation to climb up all atoms along the edge have to move. It is unlikely that this will happen at the same instant. So several jogs will be created and dislocation will gradually climb up. I wanted to avoid bringing a further new concept of jogs here. But thanks for asking.
@akithjabed5534 жыл бұрын
can we by our wish shift the dislocation line ? what you ahve shown sir ??
@pedropalmeros82263 жыл бұрын
Thank you so much! I was having trouble with this topic until i saw your video. Greetings from Mexico!
@Harshgupta-bu6jl4 жыл бұрын
sir in 3d vacancy will not extend for the whole edge line then how will the step be created?
@rajeshprasadlectures4 жыл бұрын
A good question. So in fact, one vacancy will lift only one small part of the dislocation. For the entire dislocation to climb up you require an entire row of vacancies. It is very unlikely that this will happen at the same instant, So dislocation line will climb up gradually by absorbing vacancy after vacancy. During the process, the dislocation line will not remain straight but will acquire several vertical steps called jogs.
@sunilugadi36535 жыл бұрын
at 14.06, If it is a edge dislocation what will be the scenario ?
@rajeshprasad1015 жыл бұрын
Edge dislocation cannot cross slip to an inclined slip plane. But it can climb up or down to a parallel slip plane.
@hustler66852 жыл бұрын
amazing
@sivanuja81183 жыл бұрын
How will the vacancy concentration increase or decrease? While climbing up, atoms leave the edge to occupy another vacancy, but it creates a vacant site at the edge itself, right?
@introductiontomaterialsscience3 жыл бұрын
But a similar vacant site was there at the edge before the climb up as well. So there is no new vacant site created at the edge.
@DiegoLopez-br4po3 жыл бұрын
So if there is no vancancy, the climb up wont be able to happen?
@rajeshprasadlectures3 жыл бұрын
That's right. Climb motion is linked to the interaction of dislocation with vacancy.
@user-xv9yi9ti7v4 жыл бұрын
Thankyou sooooo much
@amychen26714 жыл бұрын
If an edge dislocation is an extra half-plane of atoms, how can it be that the entire dislocation has climbed by simply shortening its front side by one atom?
@introductiontomaterialsscience4 жыл бұрын
Your doubt is valid. By the movement of just one atom on the front face, the entire dislocation cannot climb up. All the atoms of the bottom edge of the half plane have to move.
@amychen26714 жыл бұрын
@@introductiontomaterialsscience Thank you for your response sir! So all of the atoms at the bottom edge of the half plane must exchange places with vacancies for the dislocation to climb? Would that make climbing an uncommon event?
@introductiontomaterialsscience4 жыл бұрын
@@amychen2671 Climbing is indeed uncommon. First of all, it requires atomic diffusion. So it is a high temperature process. It does not happen at low temperatures. However, all atoms along the edge do not have to jump in one instant. It can happen one by one. So the dislocation line will climb in a gradual process. Some part of it may have climbed while other parts are still waiting to climb.
@amychen26714 жыл бұрын
@@introductiontomaterialsscience Thank you very much again for the clarification!
@upoldezfranky81184 жыл бұрын
Sir, what is dislocation punching mechanism?
@introductiontomaterialsscience4 жыл бұрын
I have not touched this topic in this course. This is a mechanism for nucleation of dislocation, i.e. creation of new dislocation in a crystal. If you have a precipitate or an inclusion then stresses develop due to differential thermal expansion or contraction of precipitate and matrix during a temperature change. These stresses generate a prismatic dislocation loop around the inclusion. For details see Hull, D and Bacon, D.J. Introduction to Dislocations.
@arjunaravind19315 жыл бұрын
Split portions into 3 separate videos
@introductiontomaterialsscience5 жыл бұрын
Thanks. I think it is a nice suggestion.
@pouraliakbar2 жыл бұрын
Wonderful lecture - Thanks!
@jidapa29692 жыл бұрын
Thank you so much
@ilyashamid28605 жыл бұрын
Thanks for enlightening us with Knowledge
@ShuvamNayak4 жыл бұрын
Sir, I could not understand how the screw dislocation has infinite slip plane while edge dislocation has a unique slip plane?
@vittoriopiaser92334 жыл бұрын
Shuvam Nayak it’s because the vectors t and b define the plane where the dislocation moves. A plane is uniquely defined by two vectors, if those ones are not parallel; this is the case of the screw dislocation, thereby its got an infinite number of planes where the dislocation can move. All this planes have in common that line which is the linear span of the vectors b and t (or even of just one of them, it’s equivalent since they’re parallel).
@ajayjoshi92564 жыл бұрын
bhai , you can understand in simple vector terms that one a unique plane can contain two perpendicular vectors . jaise ek vector x axis ke along hai n ek y ke along hai to only xy plane will contain both the vectors , whereas two paraller vectors be contained by multiple planes. watch 15:22 in the video both b and t vector are parallel to both plane 1 and 2
@Vinay1923 жыл бұрын
We know that dislocation motion cause plastic deformation in a material. So if their is a crack propogation in a particular direction and suddenly changes its direction to another side, is it due to the obstacle that the dislocation line changes its direction? And second, How dislocation motion can be used to differentiate between a ductile and brittle fracture?
@introductiontomaterialsscience3 жыл бұрын
Plastic deformation and fracture are different processes. Plastic deformation happens by dislocation motion. Fracture happens by crack propagation. So crack changing its direction is not necessarily related to the motion of dislocation.
@vinaythakur48053 жыл бұрын
@@introductiontomaterialsscience Okay sir...but I have still doubt that is there any relationship between the dislocation motion and crack propagation as I study in most of the research papers that dislocation emission from crack tip is responsible for the crack propagation in a material.
@introductiontomaterialsscience3 жыл бұрын
@@vinaythakur4805 You could be right. This is an advanced topic on which I am unable to comment. That's why tried to play safe by putting in the phrase' not necessarily related' in my reply. If you wish, you can tell me more about it. I would be happy to learn.
@vinaythakur48053 жыл бұрын
@@introductiontomaterialsscience You are awesome Sir.... Reminds me the humour of Dr APJ Abdul Kalam.... Although this is the problem where I'm studying hydrogen embrittlmemt effect on crack propagation in nickel and aluminium using molecular simulation...And the reason for crack propagation is the dislocation nucleation and motion that has been discussed in most of the experimental research papers.
@introductiontomaterialsscience3 жыл бұрын
@@vinaythakur4805 Best wishes for your study and research. Keep me updated.
@SANDEEP_Kumar1388 ай бұрын
Thankyou sir
@prakhartiwari64333 жыл бұрын
Sir , is dislocation effect happens in polymer material ..
@introductiontomaterialsscience3 жыл бұрын
I had not thought about it. But to answer your question I googled and found this. www.ncbi.nlm.nih.gov/pmc/articles/PMC6628581/
@prakhartiwari64333 жыл бұрын
@@introductiontomaterialsscience Thank you so much sir...
@sarthakroy52923 жыл бұрын
11:45 dislocation line moves perpendicu;lar ti itself what it means
@introductiontomaterialsscience3 жыл бұрын
The direction of motion of the dislocation line is perpendicular to the line.
@akashtiwari78059 Жыл бұрын
better yhsn then my proffesor
@kingalpha20066 ай бұрын
😊
@smarajitpunaykanti64633 жыл бұрын
Sir in a research paper I came across the term: Non basal (a+c) dislocation . Unable to understand what it is. Can you pls throw some light on it
@introductiontomaterialsscience3 жыл бұрын
This is for hcp crystals. Here the most common Burgers vector for dislocations is the {a} type, which means that the Burgers vector is along the edge length of the unit cell and its magnitude is equal to the lattice parameter a. If you now add a c vector (which is perpendicular to the basal plane) to the {a} vector you get {a+c} vector which is a less common but possible Burgers vector. It will not lie in the basal plane so it is called nonbasal.
@smarajitpunaykanti64633 жыл бұрын
@@introductiontomaterialsscience yes sir HCP. Magnesium crystal. Where can I get some more theory on it Thanks and regards