Single Crystal, Polycrystalline, Amorphous {Texas A&M: Intro to Materials}

Tutorial covering the basics of atomic and microstructure and relating material form back to material properties (isotropic/anisotropic).
Video lecture for Introduction to Materials Science & Engineering (MSEN 201/MEEN 222), Texas A&M University, College Station, TX.
engineering.tamu.edu/materials

[@alphafrye]

Exceptional lecture.Thoroughly explained and easy to understand.Thanks alot. :)

[@kanhchanaly6445]

Thank you so much for taking your time to make these lectures!

[@naruto7387]

Amazing lecture 👏, hats off for the professor

[@mohsen0619]

very informative and helpful! Thanks!

[@mamadousarr5422]

Thank you for this video, it was very useful

[@AkashDeep-do9db]

thats exactly what i was searching for. thnk u sir.

[@CaptivateWrites_110]

sir u have done a very good job. clear iminging of crystal......great

[@czdaniel1]

Prof. Patrick Shamberger made this all pretty interesting. I was looking for M.I.T 5.069 Crystal Structure Analysis course...was going to skip over watching this vid, but all the good comments got me to watch. Liked & subbed

[@sameerasaleem7966]

Really interesting..I was exactly looking for this ...thank you si much for these lectures

[@gokhansahin7251]

Thank you so much.

[@md.enamulhaque7360]

Professor, thank you very much for such an excellent lecture. I was not able to find. why do we see a material is isotropy in material size even though that material is anisotropy at crystal structure size. Thank you again professor. now I am clear about my question.

[@lilitv9723]

very good thnxx a lot! i finally understand can't believe it!

[@md.enamulhaque7360]

Hi professor, thank you for your videos, I need to ask you something. (I'm an M.Sc. student with an exam about material design and behavior very soon). Can you explain please!! why don't the notch effect is taken into account in static loading ?

[@amirshirani3374]

Thanks so much for such a nice lecture! I have a question: If we etch the surface of let’s say stainless steel, we would be able to see grains and grain boundaries. However, if we see such a sample under TEM, and focus on only one grain, would it be possible to see different crystallites (different atomic plane orientations) within one grain? Basically, I do not understand the difference of crystallite and grain. I think both has same meaning and basically grain boundary is the boundary between each grain (crystallite) with different atomic orientation. However, I see people try to distinguish between grain and crystallite which I am interested to know their difference!

[@pjshamberger]

Amir, I would agree that a "grain" is commonly used in the same sense as a "crystallite". "Grain" is probably a bit more generic, but I am essentially referring to a small crystalline domain that has a continuous crystal lattice throughout (i.e., a crystallite - a small crystal). "Grain boundary" is also general in that it can refer to a boundary between two similar crystals of different orientation (a homophase boundary) or between two domains with different crystal structures (a heterophase boundary). Also complicating matters is the existence of precipitates, which are essentially "grains within grains" (small regions of 1 particular crystal structure embedded within larger domains of another crystal structure). So what you might define as a "grain" at one lengthscale might actually be composed of more than one phase of you look hard enough.

[@StevenSchoolAlchemy]

Good job

[@nickycchua]

Hi, thank you for your very informative video, can I know what do they used to grind Natural Diamond and HPHT diamonds, or do you have any information on grinding for Natural diamonds and HPHT Diamond Tools. thank you in advance...

[@ogwanginnocent9449]

Nice

[@huayingzhong9728]

Thanks!!👍

[@manuelpena3988]

Hi, thank you for your videos, I need to ask you something. (I'm a student with an exam about this very soon). I think I've allways been taught that in the cold working what you change is the shape of the grains, but not their nature, so that's why after the cold working it appears what is called strain hardening in the direction where the grains have been strained. BUT as you didn't change the phisical properties of the bonding, you still have the same measure of the Young Modulus. To me it makes sense that is you only strain the grains, but don't reorientate the crystals to a prefered direction, then the Young Modulus should not change. In the other hand it also makes sense to me that in the straining of the material you lose some randomness of the material and so you change the Young Modulus. Being a student I don't have any lab to test wich of the assumptions is true, Could you please explain it to me? Thank you so much.

[@pjshamberger]

Your description: "...in cold working what you change is the shape of the grains, but not their nature, so that's why after the cold working it appears what is called strain hardening in the direction where the grains have been strained..." is accurate. You change grain shape and orientation, but **after** removing the load, the crystal will return to its equilibrium structure (bond lengths will relax to their equilibrium distance). However, your second point: "...if you only strain the grains, but don't reorientate the crystals to a preferred direction, then the Young Modulus should not change. In the other hand... in the straining of the material you lose some randomness of the material and so you change the Young Modulus." is also correct. Essentially, if you only cold work to a small degree (change the concentration of dislocations, but don't induce much preferred orientation), you could expect the Young's Modulus to remain unchanged. However, if you do induce significant preferred orientation (AND if Young's Modulus is strongly anisotropic in a particular crystal system), then you could reasonably expect to modify Young's Modulus to some degree in one particular direction.

[@alijutt3675]

could you please let me know that i read some articles that this is 100 single crystal cu or 110 or 001 single crystal copper. so what dost it mean? it means that 100 single crystal copper does not have any other direction.? please let me know and clear my concept

[@pvp9897]

@13:28 Poly crystalline random should be anisotropic and textured be isotropic !?

[@charvi7317]

Sir i also have a question Gypsum is polycrystalline or single crystal Because in a book it's crystallization process shows it's made of spherulites

[@varundolia2192]

Hi, thanks a lot for such a cogent video. I had one question, many a time, people interchangeably use the terms 'grains' and 'crystals'. I suppose, even you did the same in one of the sections in the video. Can you please help me understand the nuances here? Can a grain be considered a single crystal?

[@pjshamberger]

Varun - this is exactly right. Usually when we are looking at a polycrystalline material, we will refer to a single crystal domain as a "grain". Things can get a little bit more complicated if you have small precipitates (i.e., a secondary phase) occuring within one "grain". But usually, when folks use the word "grain" for a polycrystalline solid, they are referring to a single phase that has a continuous crystal lattice throughout, and it is separated by a neighboring "grain" that could be the same phase (or a different phase) by a "grain boundary" (where the lattice orientation generally changes across the grain boundary).

[@varundolia2192]

@@pjshamberger Thanks a lot, sir. This made it clear.

[@handoost1514]

The difference between polycrystalline and multicrystalline ???

[@charvi7317]

Also is table salt monocrystalline or polycrystal line

[@serden8804]

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[@abojebreel6433]

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[@salahmasri501]

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[@parkerflop]

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[@CaptivateWrites_110]

sir u have done a very good job. clear iminging of crystal......great