César Alberto Núñez López

6 жыл бұрын

Fe-C phase diagram and the eutectoid reaction

6 жыл бұрын

Invariant Points, reactions and eutectic

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@rodinafaisel76814 ай бұрын

Thank you so much. I've been struggling for a whole semester but thanks to you i finally understood everythig. Best regards

@kayagunduz74904 ай бұрын

thanks sir

@cesar_nunez4 ай бұрын

Most welcome

@solounomas05 ай бұрын

Very clear explanation!!

@cesar_nunez4 ай бұрын

Glad you think so!

@fakel1ght5447 ай бұрын

Your voice makes me feel like ronaldo is teaching

@kamilkarakaplan1293 Жыл бұрын

Cihangir hocama selamlar 😂😂

@maarten-pz9oq Жыл бұрын

You are a legend, thank you!

@obadiahdadzie3056 Жыл бұрын

Thank you🔥🔥🔥🙇‍♀️🙇‍♀️

@Fracically2 жыл бұрын

I’ve been looking for a video that explains the relationship between TTT from the phase diagram. Your video explains what I’m looking for so thank you!

@fatemahmehrabi70712 жыл бұрын

hello i have one question..i have dilatometric results and how can i draw cct diagrams with these results? thank you for your answer

@cesar_nunez2 жыл бұрын

It is possible to use dilatometric results for making a model of transformation kinetics, making the proper corrections, for instance, by the use of the Kop et al method. Read the article of Gomez et al (M. Gómez, S. F. Medina, G. Caruana, "Modelling of Phase Transformation Kinetics by Correction of Dilatometry Results for a Ferritic Nb-microalloyed Steel", ISIJ International, vol. 43, Issue 8, 2003) for some ideas about this.

@fatemahmehrabi70712 жыл бұрын

@@cesar_nunez thanks for your answer but this article is unavailable.

@cesar_nunez2 жыл бұрын

@@fatemahmehrabi7071 Sorry about that! Try then the article by Garcia de Andres et al ("Application of dilatometric analysis to the study of solid-solid phase transformations in steels", Materials Characterization, 2002 (48) pp. 101-101) digital.csic.es/bitstream/10261/34076/1/Mater%20Charact_2002_Garcia_de_Andres.pdf I hope this link works.

@fatemahmehrabi70712 жыл бұрын

@@cesar_nunez great.thank you for your answer.

@digontadey873 жыл бұрын

thanks a lot...now my math concept is cleared.

@gustavbjerrum87463 жыл бұрын

Tak

@tomasfernandez28543 жыл бұрын

Gracias César Alberto

@ashutoshshivarkar22563 жыл бұрын

thanks man great video

@jeanclaudematias32653 жыл бұрын

Thank you Very Much!

@muddassarhussain88713 жыл бұрын

Great teaching ! Please make a video on kinetics of phase reactions and transformation in detail

@granttekell39394 жыл бұрын

Thank you so much Dr. Núñez!! This makes so much sense now!

@stanisawkarubin98134 жыл бұрын

What is the difference between Eutectoid and Monotectoid when in both we are receiving 2 solids from one solid phase?

@cesar_nunez4 жыл бұрын

Excellent question! I didn't discuss that and it is certainly deceiving. There are two main differences; the first one is that in monotectoid reactions one solid transforms to two different solids of the same crystal structure but different compositions whereas for the eutectoid reactions, one solid transforms in two different solids of different crystal structures and compositions. The second difference is the presence of a miscibility gap in the monotectoid reaction, which can be seen as a “cap” surrounded by the original solid phase that engulfs the two solid phases it is going to be transformed into. You can see an example of this in commons.wikimedia.org/wiki/File:Monotectoid_reaction.png

@stanisawkarubin98134 жыл бұрын

@@cesar_nunez Now it is more than clear. Thank you!

@lukeedward8934 жыл бұрын

roll tide

@aquvamechanic52404 жыл бұрын

i got it teşekkürler

@streetview30454 жыл бұрын

thank you sir

@supriyasingh68084 жыл бұрын

voice is not clear..😢

@cesar_nunez3 жыл бұрын

Sorry about it!

@assadsafaey4324 жыл бұрын

Thank you so much for your this helpful video

@tyan43804 жыл бұрын

Sorry i didn’t understand why u proceed the following steps all from 0 second , since ur calculation of percentage takes accounts of previous step loss of austenite ,they transformed into others, then to calculate whats left and what they are going to change further should start from the point of last step ending , The shape of transformation should be a staircase isnt it?

@cesar_nunez4 жыл бұрын

Excellent point! This is something which is not as straight forward as it might seems to be at first. Whatever we can discuss about this, keep in mind that TTT diagrams are made by quenching to ONE single temperature and waiting until full transformation; when using the TTT diagram in the way we do (quenching to several different temperatures) we are pushing the concept a little bit too far; none the less, it’s still a good first approach. Now, also keep in mind that, when quenching a material, heat transfer takes place at the surface of the material, so the center of the material is the last part to cool down; finally, we are working with a log-log scale, so that “numbers” at the far left are orders of magnitude smaller than numbers to the right; finally, control of temperature is not perfect in practice. Taking all this into account, although your idea is “quite right” it needs a small correction (and it would require to assume that the full material is at the same temperature everywhere at any time, which requires a very small sample with a very high relationship Area to Volume and a very high heat transfer coefficient); if that is the case, it wouldn’t be a “stair” but rather a “straight line” with a slope equivalent to the “cooling speed” of the quenching process departing from the starting cooling temperature. That is way, assuming that your quenching is fast enough (“very high” cooling speed), then the assumption of a straight vertical line (infinite slope) is the other option you have, and this is the one I’m using. In practice, what we need to do is a simulation of the heat transfer and analyzing the thermal path of each part of the material. That is way we also have the CCT Diagrams which it is a more practical option.

@brielleibe85035 жыл бұрын

Wow, this was awesome! Made so much sense! Thank you so much, great video!

@Steamboatjohnson99345 жыл бұрын

i hope your throat gets better, César. thanks for the wonderful info.

@georgechahir94455 жыл бұрын

Thanks bro

@mertaypar88915 жыл бұрын

YOU ARE A SAVIOUR!!!!!!! I was sick at that lecture and i wasn't able to understand this from slides. Thank you so much, really really appreciated!!

@fatihakcay42605 жыл бұрын

Thaanks prof for the video. Ttt questions is nice!

@awaken57395 жыл бұрын

Thanks alot sir ☺️

@onomono19995 жыл бұрын

Thanks a lot for your videos, they helped me so much! You deserve waaay more than 784 views.

@ReasonablePerfection5 жыл бұрын

Why teachers in classrooms are so fucking dumb while on KZread teachers are great !?

@ReasonablePerfection5 жыл бұрын

Thank you!!

@akaneru2905 жыл бұрын

U r the best, thank u very much...

@azrilntdrill5 жыл бұрын

thank you !!! Why cant the profs in my school be as straight forward as you about this concepts.

@whiteseed55 жыл бұрын

Great video!

@brightonpamire78745 жыл бұрын

wooooow, you've just made it simpler .AWESOME

@ogantino5 жыл бұрын

gracias Cesar, saludos de Argentina!!!

@adityapaliwal50655 жыл бұрын

thank you so much. really helpful !

@amatoallahouchen58945 жыл бұрын

GREAT VIDEO THANKS PROFESSOR

@adelbanaweer13175 жыл бұрын

Thanks alot for the amazing information

@mrmojojp15 жыл бұрын

Thank You

@niatash80586 жыл бұрын

Tq SOOOOOOOOO much

@MrSpaceboyy6 жыл бұрын

you are the man

@Picky21066 жыл бұрын

Is it possible to calculate the resulting hardness of say example 2? would it be correct to say 50% Bainite at 41HRC and 50% Martensite with 57HRC results in a hardness of 20.5+28.5=49HRC? Thanks

@cesar_nunez6 жыл бұрын

On average, yes. What you propose is known as "The proportions rule" and it applies to this example in the way you present it. Excelent! It is important to recognize that, in reality, you will have regions with different microstructures and properties; hence, this average value might be of significance or not, depending on the purpose of your answer. For example, it might be that you have a harder surface than the core, which will be benefitial in applications where you need certain ductility for the whole element with a hard surface that might give it stiffness. In such case, this average might no be as imprtant as the distribution of microstructures.

@Picky21066 жыл бұрын

Thank you for your detailed answer and quick reply! very helpful!