No wonder why students fight so much during JEE exam. Because of professors like him. I had trouble in understanding this concept since my college days but after watching this course till here I am feeling so confident about my concepts. Thank you sir. May you live long and healthy life.
Sir, please add me to your fan followers list. Never had I ever enjoyed learning material science as I did after visiting your lecture series. Your explanation is really covering every nuance, like why >2% carbon is called cast iron (because melting point decreases & hence it is beneficial to use in casting). Sir, maybe I would run out of words to admire your explanation. Just to let you know, (without any intention to offend anybody), I started your lecture series after going through IIT Roorkee & IIT Bombay lectures on Phase diagrams. Your lectures & your explanation is just beyond comparison. Thank you for your efforts!
A Humble request to Material Science Teachers... please do draw the Iron Carbon Diagram rather than displaying it in the ppt. This lecture gave me lot of confidence after 5 years to read the concept further. Thanks Sir.
Dear Sir, thank you very much for such valuable, exceptional videos. In all videos you are explaining each topic in such a systematic and clear way that it can be easily understood. I wish I got a course from you, your students must be so lucky.
Dear sir, I have started to gain interest in materials Sc. after watching your videos. Even an average student can understand the concepts easily by virtue of your teaching skills. Thank you so much sir
Excellent Explanation My Bestest Phy Metallurgy teacher is you sir. I have seen all my syllabus from your lecture. Thank you for your knowledge and hard working towards us. Thank you very much.
thank you proffesor for giving your knowledge for us. I am watching your videos from Türkiye and i must to say that this is my first time when i learn Fe-C phase diagram with so much fun and enjoy.
I think this is probably the most easy way of explaining the FeC diagram. Looking at the views and upload history I wasn't impressed. After going through many videos and the complexity I found everywhere , I thought Y can't I give a try to this! And you proved me that I arrived to the right spot to learn FeC diagram. Thank you so much sir. With love from Tamil Nadu.
Sir , If FCC has better APF and better properties compared to BCC , why does iron shift from austenite (FCC) to D-ferrite(BCC) at higher temperatures ?
Hi sir, There are three solid solid reaction eutectoid, peritectoid and monotectoid I've understood first 2, what is monotectoid reaction, can you help me out
Sir, why does the crystal structure BCC (delta ferrite) convert to FCC (Austenite) upon cooling and then again FCC (Austenite) converts back into BCC (alpha ferrite) upon further cooling for Iron?
Sir I want learn about formation of stainless steel (austenitic, duplex etc.) and PWHT. Do you have a video about stainless steel phase diagram and post weld heat treatment. I will be grateful if you can share. Thanks in advance and with my best wishes..
2:06 Shouldn't 'Intermediate Compound' be a better term instead of intermetallic, as Carbon itself isn't a metal, or the is the term applied to non-metallic components too?
Strictly speaking, you are correct. However, it has become common to call Fe3C also as inter metallic compound despite the fact that one of the components is not metallic.
Sir i referred the book callister's material science and engineering and i found the structure for austenite is fcc but you have mentioned ccp for the same... This creats a little doubt.. Would you please explain?
I am trying to make a distinction between crystal and lattice. As I have explained elsewhere, Crystal=lattice +Motif. In my lectures I reserve FCC for lattice. Thus calling austenite FCC gives only a partial information about its crystal structure. Diamond and NaCl also have FCC lattice but have very different motif. Diamond has two atoms of the same kind as its motif whereas NaCl has two atoms of different kinds as its motif. Motif is CCP is different from both of these. Its a single atom motif. Thus CCP is a better description of the crystal structure of austenite than FCC.
Because, steel, I mean plain carbon steel, an alloy of Fe and C, is THE MOST IMPORTANT engineering alloy. Think of buildings (steel reinforcement of concrete), cycles, cars, planes, ships, ....
Sir, I have a question * How actually do we control the carbon percentage in iron, Is there a process?(like we have cyaniding carburizing, but those are limited to surface) * If yes then what are they if not then is it means that once we have a given steel with a given percentage of carbon, there is nothing we could do to change the composition, like you said we don't meet steel.
As FCC is close-packed it can also be called CCP. FCC (face centered cubic) describes the unit cell (atom in the centre of each face and at the corners of the cube) - CCP (cubic close packed) describes the packing on the [111] plane of the FCC structure.
Actually it is not the Fe-C phase diagram [equilibrium phase diagram], what we are seen in the video is a Fe-Fe3C phase diagram [Non equilibrium diagram] because cementite is a meta stable phase, And graphite is a Stable Phase.
@@_paulmusyoka_ Calling it CCP is preferred to FCC. CPP means FCC lattice with single-atom motif. There are other crystals also which have FCC lattice, e.g.diamond. But the diamond is FCC lattice with two atom motif. In other words FCC only give the lattice whereas CCP gives both the lattice (FCC) as well as the motif (one atom) which is a more complete description of the crystal structure.
The composition 0.8 wt%C is the eutecTOID composition. Eutectoid reaction is completely solid-state reaction, there is lo liquid involved. Thus it does not correspond to the lowest melting temperature. But it does correspond to the lowest temperature at which ferrite+Fe3C transform completely to austenite. The eutecTIC composition corresponds to the lowest melting point. It is 4.3% C.
Sir What is upper critical temperature and lower critical temperature and what is the significance of these temp What are the values of the above temperatures
the lower critical temperature is the eutectoid temperature. It is 725 C for plain C steels. Below this the steel has ferrite and cementite phases in its microstructure. On heating above this temperature transformation to austenite begins. At the upper critical transformation transformation to austenite completes and one has 100% austenite. For hypoeutectoid steels, the upper critical temperature varies between 910 C and 725 C (temperature of the gamma/ gamma+alpha boundary). For hypereutectoid steel it is the tempearture corresponding to gamma/gamma+cementite boundary.
At one level, you can call it a composite. Ferrite is soft and ductile. Cementite is hard and brittle. Pearlite, a two-phase mixture of ferrite and cementite, can be considered an in-situ composite. The adjective 'in-situ" is to indicate that we did not separately make ferrite and cementite and then mixed them. The mixture was created internally during the decomposition of austenite on cooling. This is the reals difference between pearlite and a composite like GFRP (Glass Fibre Reinforced Plastic). Here, glass fibres and plastic are prepared separately and then combined to give the composite.
This is a good question. Alpha iron is ferromagnetic. It transforms into a paramagnetic form above the Curie temperature of 770 C. This paramagnetic form was originally called the Beta iron. Although the magnetic state changes, the crystal structure of both alpha and beta iron is the same: bcc. So later, this classification was discontinued and beta iron was absorbed in alpha iron to indicate that there is no change in the crystal structure.
Sir this is a phase diagram and we are getting alloys at distinct point on phase diagram and not compound. An alloy is a mixture not a compound so why you say Fe3C cementite as a compound? It should be mixture? Please someone clarify it.
Fe3C (cementite) has a distinct crystal structure (Simple Orthorhombic with four formula units per cell) and occurs at a fixed composition of 25 atomic % or 6.67 weight percent C. Thus it is called a compound. In case of solid solution, there should be possibility of some variability in composition.
Sir, I followed Callister [5th edition] to revise Fe-C diagram, on page 447 under 10.19 Iron-Iron Carbide Phase Diagram topic, it says Austenite has FCC structure. Here you said it is CCP. Please help.
My CCP is the same as his FCC. I insist that CCP is a more precise term for the structure than FCC. Note that Crystal=Lattice +Motif. FCC is a lattice. Thus just saying FCC is not exactly the correct description of the crystal as the information of motif is not given. So when Callister calls austenite FCC he assumes that motif is a single atom. A better phrase will thus be monatomic FCC. I use CCP for a crystal with FCC lattice and a single atom motif. Thus CCP=Monatomic FCC but not equal to just FCC.
The best explanation you could find on the internet for the Fe-C equilibrium diagram.
exactly
Yep
No wonder why students fight so much during JEE exam. Because of professors like him. I had trouble in understanding this concept since my college days but after watching this course till here I am feeling so confident about my concepts. Thank you sir. May you live long and healthy life.
JRE joe rogan experience
You must be a celebrity teacher soon.Legend !!!
He already is :)
He's like the Wayne Gretzky of teaching materials science. The GOAT
Sir, please add me to your fan followers list. Never had I ever enjoyed learning material science as I did after visiting your lecture series. Your explanation is really covering every nuance, like why >2% carbon is called cast iron (because melting point decreases & hence it is beneficial to use in casting). Sir, maybe I would run out of words to admire your explanation. Just to let you know, (without any intention to offend anybody), I started your lecture series after going through IIT Roorkee & IIT Bombay lectures on Phase diagrams. Your lectures & your explanation is just beyond comparison. Thank you for your efforts!
I never gone through such a beautiful lecture in Fe-Fe3c Phase diagram before. Awesome sir.
sir excellent lecturer because material science is one of the toughest subject for understanding
The best part is his voice is crystal clear even at 2X speed
Yeaa totally agree
After watching lot of videos, I came across this.. absolute gold..for the first time something made sense and I could understand..thank you sir!
The best explanation ever on RUclips about Fe-C diagram, thank you sir 🙏
A Humble request to Material Science Teachers...
please do draw the Iron Carbon Diagram rather than displaying it in the ppt.
This lecture gave me lot of confidence after 5 years to read the concept further.
Thanks Sir.
I agree
The most simplest explanation I ever had that I've miss during my 3year course of Diploma in Material Science Engineering and Technology at MSU-IIT.
have you ever seen such type of ligendry man!!! Thank u so much sir.
Master at work. What an amazing lecture!!
Dear Sir, thank you very much for such valuable, exceptional videos. In all videos you are explaining each topic in such a systematic and clear way that it can be easily understood. I wish I got a course from you, your students must be so lucky.
I am in NIT Allahabad and I am so grateful to you for such a amazing lectures on RUclips❤❤ thank you 🙏
Very helpful explanation; thank you so much!
Such a wonderful simple explanation.
Brilliantly explained!!
Thank you sir
Dear sir, I have started to gain interest in materials Sc. after watching your videos. Even an average student can understand the concepts easily by virtue of your teaching skills. Thank you so much sir
Excellent Explanation My Bestest Phy Metallurgy teacher is you sir. I have seen all my syllabus from your lecture. Thank you for your knowledge and hard working towards us. Thank you very much.
pass aa brooo
pakkaaa
@@kkpdevarakonda8531 ee subjet doubt ante waste ee
There are tougher subjects than this
Good explanation...I missed this type of lecturer during my engineering time:-(
best video i've seen till now for this concept
❤ , for the dedication and wonderful explanation .....
The best explanation I have ever seen thank u sir
thank you proffesor for giving your knowledge for us. I am watching your videos from Türkiye and i must to say that this is my first time when i learn Fe-C phase diagram with so much fun and enjoy.
superb explaination sir !! thank you very much
Best explaination i seen ever.. Thanx
much thanks ur the best material science teacher I've seen so far keep it up thnkkuu
Thank you very very much you helped me to understand the Fe-C diagram for my exam
Best explanation I have ever seen ♥️♥️♥️♥️♥️♥️👌👌👌 thanks sir
Sir,
Really explained in very easy manner.... coloured sketch pened diagram made understanding easy and clear
Completely satisfied. Thank you sir
Thank you really could understand this topic easily
Very simple explanation. Thank you so much
i learnt so much from this presentation
I think this is probably the most easy way of explaining the FeC diagram. Looking at the views and upload history I wasn't impressed. After going through many videos and the complexity I found everywhere , I thought Y can't I give a try to this! And you proved me that I arrived to the right spot to learn FeC diagram. Thank you so much sir. With love from Tamil Nadu.
SIR,you are a true master class
sir is the three invarient reaction is due to the different crystal structure of iron on different temperature.
best Fe-C phase diagram explanation
thank you Sir
Excellent explanation ☺️
Just excellent sir
Super explained sir.....
Excellent teaching...
Sir , If FCC has better APF and better properties compared to BCC , why does iron shift from austenite (FCC) to D-ferrite(BCC) at higher temperatures ?
Well explained sir..thanks
Hi sir,
There are three solid solid reaction eutectoid, peritectoid and monotectoid
I've understood first 2, what is monotectoid reaction, can you help me out
Thanks for this lecture.....
May I would meet you in future and touch your feet.Thanks a lot and i will pray for your long life so that you could teach as long as possible
Best of Best👍
Sir excellent lacture
Sir, why does the crystal structure BCC (delta ferrite) convert to FCC (Austenite) upon cooling and then again FCC (Austenite) converts back into BCC (alpha ferrite) upon further cooling for Iron?
Very nice sir . Just a request if u could have said something about pearlite microstructre
Very understandable
Short of word's but Oo Man you are a beyond a Lengend.......
Thanks Alot dr ❤️👌💯
Sir I want learn about formation of stainless steel (austenitic, duplex etc.) and PWHT. Do you have a video about stainless steel phase diagram and post weld heat treatment. I will be grateful if you can share. Thanks in advance and with my best wishes..
I became fond of MSc,thank you sir
Msc which subject ru?
FINALLY REACHED THE RIGHT PLACE
How can I study about Monotectic and Pretectoid?
The best sir. 💯
💯💯💯
Nice sir
During solidification... From liquid phase does the latent heat varies with different phases and carbon percentage?
Yes.
2:06 Shouldn't 'Intermediate Compound' be a better term instead of intermetallic, as Carbon itself isn't a metal, or the is the term applied to non-metallic components too?
Strictly speaking, you are correct. However, it has become common to call Fe3C also as inter metallic compound despite the fact that one of the components is not metallic.
Sir i referred the book callister's material science and engineering and i found the structure for austenite is fcc but you have mentioned ccp for the same... This creats a little doubt.. Would you please explain?
I am trying to make a distinction between crystal and lattice. As I have explained elsewhere, Crystal=lattice +Motif. In my lectures I reserve FCC for lattice. Thus calling austenite FCC gives only a partial information about its crystal structure. Diamond and NaCl also have FCC lattice but have very different motif. Diamond has two atoms of the same kind as its motif whereas NaCl has two atoms of different kinds as its motif. Motif is CCP is different from both of these. Its a single atom motif. Thus CCP is a better description of the crystal structure of austenite than FCC.
thank you sir
sir in a book it is mentioned that in peritectic reaction the composition of delta iron is 0.08%
No , it is 0.8 % only
@@gangaraju8589 in my book , its 0.83
Nice
manggggggggggggggggg danger bhau
Sir, during eutectoid reaction, how BCC-FCC transformation makes austinite non-magnetic?
Why austenite is non-magnetic whereas ferrite is magnetic is an interesting question. I have not found the answer to this question yet.
I wish i had this lecturer in my uni. I'm Pakistani and went to Malaysia to study.
Free me hai dekh lo / ya hmse sampark mai phase dunga
thankyou sir
Professor I have question.If you were asked why Fe-C phase diagram is so important ,what would you say?Could you give me a short explanation.
Because, steel, I mean plain carbon steel, an alloy of Fe and C, is THE MOST IMPORTANT engineering alloy. Think of buildings (steel reinforcement of concrete), cycles, cars, planes, ships, ....
Thank you Sir ❤️❤️❤️
Thank you sir for hard you
Thanks Sir❤✌
Thank you sir🙏
Why is cementite called an intermetallic compound ? Clearly Carbon is not a metal. Don't intermetallic compounds imply compounds between two metals ?
Sir, I have a question
* How actually do we control the carbon percentage in iron, Is there a process?(like we have cyaniding carburizing, but those are limited to surface)
* If yes then what are they if not then is it means that once we have a given steel with a given percentage of carbon, there is nothing we could do to change the composition, like you said we don't meet steel.
Carbon concentration of steel cannot be changed in solid state (except at the surface, as in carburising and decarburising).
tq sir
Like no. 1k 💯
I think *The Soul of engineering* exists in Fe-C diagram ....
Sir, I think Gamma iron or austenite is FCC structure
As FCC is close-packed it can also be called CCP. FCC (face centered cubic) describes the unit cell (atom in the centre of each face and at the corners of the cube) - CCP (cubic close packed) describes the packing on the [111] plane of the FCC structure.
Actually it is not the Fe-C phase diagram [equilibrium phase diagram], what we are seen in the video is a Fe-Fe3C phase diagram [Non equilibrium diagram] because cementite is a meta stable phase, And graphite is a Stable Phase.
You r so slow.... But still give a lot of help... Thanks
so simple to learn the unuderstandable term.......
Hello, thankyou for the enlighting video. Is it CCP Austenite or Gamma Austenite?
Austenite is the name of the phase. Gamma is the Greek symbol for the phase. CCP (Cubic close-packed) is the crystal structure.
But Gamma Austenite is FCC
@@_paulmusyoka_ Calling it CCP is preferred to FCC. CPP means FCC lattice with single-atom motif. There are other crystals also which have FCC lattice, e.g.diamond. But the diamond is FCC lattice with two atom motif. In other words FCC only give the lattice whereas CCP gives both the lattice (FCC) as well as the motif (one atom) which is a more complete description of the crystal structure.
thanks Sir
someone can adding turkish subtitle pls thanks
why the 0.8 carbon is not the lowest melting point in the whole alloy system???
The composition 0.8 wt%C is the eutecTOID composition. Eutectoid reaction is completely solid-state reaction, there is lo liquid involved. Thus it does not correspond to the lowest melting temperature. But it does correspond to the lowest temperature at which ferrite+Fe3C transform completely to austenite.
The eutecTIC composition corresponds to the lowest melting point. It is 4.3% C.
Sir
What is upper critical temperature and lower critical temperature
and what is the significance of these temp
What are the values of the above temperatures
the lower critical temperature is the eutectoid temperature. It is 725 C for plain C steels. Below this the steel has ferrite and cementite phases in its microstructure. On heating above this temperature transformation to austenite begins. At the upper critical transformation transformation to austenite completes and one has 100% austenite. For hypoeutectoid steels, the upper critical temperature varies between 910 C and 725 C (temperature of the gamma/ gamma+alpha boundary). For hypereutectoid steel it is the tempearture corresponding to gamma/gamma+cementite boundary.
🙏🙏🙏
Thankyou
Sir, is pearlite consist multi phases??
Yes, it consists of alternating lamellae of ferrite and cementite.
At 7:19 he sounds like Dr Zola from captain America 2
Sir,is pearlite composite??
At one level, you can call it a composite.
Ferrite is soft and ductile. Cementite is hard and brittle. Pearlite, a two-phase mixture of ferrite and cementite, can be considered an in-situ composite.
The adjective 'in-situ" is to indicate that we did not separately make ferrite and cementite and then mixed them. The mixture was created internally during the decomposition of austenite on cooling. This is the reals difference between pearlite and a composite like GFRP (Glass Fibre Reinforced Plastic). Here, glass fibres and plastic are prepared separately and then combined to give the composite.
Supb
I wish that u are my teacher
In Fe-Fe3C phase diagram why we don't have beta phase instead we are having gama and delta phases
This is a good question. Alpha iron is ferromagnetic. It transforms into a paramagnetic form above the Curie temperature of 770 C. This paramagnetic form was originally called the Beta iron. Although the magnetic state changes, the crystal structure of both alpha and beta iron is the same: bcc. So later, this classification was discontinued and beta iron was absorbed in alpha iron to indicate that there is no change in the crystal structure.
@@introductiontomaterialsscience Thank u so much sir for replying 🙏
Sir this is a phase diagram and we are getting alloys at distinct point on phase diagram and not compound.
An alloy is a mixture not a compound so why you say Fe3C cementite as a compound?
It should be mixture?
Please someone clarify it.
Fe3C (cementite) has a distinct crystal structure (Simple Orthorhombic with four formula units per cell) and occurs at a fixed composition of 25 atomic % or 6.67 weight percent C. Thus it is called a compound. In case of solid solution, there should be possibility of some variability in composition.
Sir, I followed Callister [5th edition] to revise Fe-C diagram, on page 447 under 10.19 Iron-Iron Carbide Phase Diagram topic, it says Austenite has FCC structure. Here you said it is CCP. Please help.
My CCP is the same as his FCC. I insist that CCP is a more precise term for the structure than FCC. Note that Crystal=Lattice +Motif. FCC is a lattice. Thus just saying FCC is not exactly the correct description of the crystal as the information of motif is not given. So when Callister calls austenite FCC he assumes that motif is a single atom. A better phrase will thus be monatomic FCC. I use CCP for a crystal with FCC lattice and a single atom motif. Thus CCP=Monatomic FCC but not equal to just FCC.