For someone whose native language is not English, who is studying mechanical engineering and is due to take a materials final, I find these videos incredibly helpful and am grateful I found them. Thank you very much for simplifying the issues in question. Greetings from Argentina!
Exquisite delivery! Several centuries' worth of knowledge effectively and clearly disseminated in a few short lectures. I doff my hat for you Dr Wu. Thank you so much.
i have my intro mat sci final tomorrow and you genuinely saved my ass...please continue to drop in those little logical explanations of yours they are very helpful in avoiding simple memorization
Just watched the three videos on material science you have and WOW. You explain just the fundamentals and very well, and everything makes sense. Thank you so much for making these!
A lot of people have already said it, but thank you very much again. You managed to fit two months of a semester or even more into 3 videos lasting just an hour in total. God bless teachers like you, who make the education accessible and easily understandable.
This (paired with the first two videos) is an absolutely incredible introduction. I feel like i understand the heat treatment process 10000x better, wow.
Thanks a lot Dr. Wu. You have the best explanations on youtube. I don't generally understand this stuff but you made it so clear that even I was able to clearly understand it. You basically summarized my 2 hour lecture in 15 minutes. Would have loved to have you as my teacher. Once again thanks a lot and I wish you did more of these videos on other topics that would really help ......
Thanks a lot. I genuinely didn't know a thing about metallurgy and metals. But as I work closely with metal manufacturing I forced myself to understand the basic theory of how it is made. This video of yours explains so clearly the factors that affect the hardening of metals. I am so glad that professionals like you would share things that You've spent years to study and make it so easy to understand. really appreciate!
The three videos you have produced about phase diagrams, phases of steel, and this one are extremely well done. They are very easy to understand and I am grateful that you spent the time to put them together. Do you have a video on the bronze (Cu-Sn) phase diagram, or know of one?
Thanks! Appreciate the comment and glad to hear it helped. Unfortunately, I haven't got a video on Cu-Sn phase diagrams. Doing a quick search I can see there's a lot more going on in that specific system. The content out there seems mostly focused on research papers
Your way of explanation helps me to recall of what I studied from mechanical engineering.. especially your pronunciation easy to follow first non native English spoken person
Dr. Wu.. Thank you. I'll be watching this video multiple times to better my gas turbine engine reports and the material run time damages they under go through out the engine's service life. I perform inter-stage inspections by video-scope and often wonder why certain materials and rotating parts have accelerated loss of strength and other areas and material types don't. It seems as if the single crystal process is the latest high temp, high tensile strength most tolerant in the engines I represent. Thanks for your time and mostly for simplifying the video.
Thanks. Glad to hear it was useful. Heat is one of the major factors which can influence the strength of a metal; impacting the grain structure and phase composition
Excellent video. I would like to include practical examples of the process for all three hardening techniques with constituents mentioned with weight or percentage to visualise the actual alloying process creating strength, ductility and resistance to corrosion
Thanks Billy Wu ....Your videos have been so helpful and gives lucid explanation. Thank you so much. I have one request. If you can make a video on Gibbs Free energy, it would be great.
Sir. indeed an informative video, keep enlighten us. I request you to make some shots of TMT Bars (Primary and Secondary), and causes of failures. Thank you.
Thanks and glad to hear it was useful. Thanks for the suggestion for future videos. I have a list of potential next ones, but just need to find the time to create them
When cold worked via the milling process, what level of hardness could one expect for the outer shell of 303 stainless steel? Thank you for such an informative video.
Dr wu can you please explain to me why work hardening/cold working is defined as making grains smaller? To me, cold rolling elongates the grains, which by definition makes them bigger, or at the very least longer and post normalized recrystilization then allows new smaller equiaxed grains to nucleate. I only have a hnd in materials science, but I’ve worked in a steel mill for years as a metallurgist and this has always bothered me. I understand the area of the grains technically decreases but when you look at the steel under a microscope we always refer to cold formed steel as having larger grains and normalized steel as smaller more uniform grains. Seems to me as one of those things that’s different in theory than practical applications.
Hello Dr. Wu I have a requesting you to make video on Fe-C Diagram with your lecture where non metrologist can understand easily. Please it is my personal request to you. it helps me and others can get benefits on your lecture as always
Mixing things up. Deformation in high temperatures and grain size evolution vs cold working. The Hall-Petch equation cited is only valid for ambient temperature !
Thank you Doctor Wu for this very easy to understand video. I have one doubt regarding precipitated hardened stainless steel. We regularly use SS17-4 PH. The problem is the physical properties vary a lot after H950 for every part. We currently procure the material in Condition A (Solution annealed from 1042 °C), after doing the major boring/drilling/turning job, and then age harden it to H925 for 1 hour/25 mm cross section thickness (also acting as stress relieving). The problem is that we are getting elongation ranging from 8% to 15% and hardness from 34 to 43 HRC, which is too broad to categorise in any HT condition. Please suggest what should be the ideal way to process the material.
a. It may be seen that the time to peak hardness and the peak hardness itself are a function of the ageing temperature. Why does the curve at 30 °C not obey this general trend ? b. It may be seen that at the temperatures 110 and 130 °C an initial hardness plateau occurs before the peak hardness is reached whereas this is not found at the other temperatures. i. Why is such a plateau found at those two temperatures and not at the higher temperatures? ii. Would you expect such a plateau also at 30 °C, although at longer times? help me with these questions
Usually alloys which have a composition where at room temperature they exist in a 2-phase solid region. Some examples might be aluminium, titanium and nickel alloys but there are many others. The key is that you can create this second phase to hinder atomic movements and strengthen the material
Hello, in the TTT-diagram, shouldn't the cooling lines be straight (temperature held stable) when entering the red pearlite part? Or is that not required? thanks!
Great question. The challenge with precipitation hardened alloys is that they are thermodynamically unstable and eventually will revert back to the thermodynamic composition and lose the strengthening benefits of the heat treatment (though this can be quite slow in some instances). Alternatively, dispersion strengthened alloys can also provide good strength by mixing in small particles of oxide materials into a metal matrix. The advantage here is that since the 2 phases are thermodynamically stable relative to each other you don't lose the strength at higher temperatures as precipitation hardened materials would.
I adapted it from "Materials science and engineering" by William Callister. Fantastic foundational book for material science. Redrew it so that I can animate it so the exact positions might be slightly out but the core principles are the same
@@BillyWu Found it online, excellent. Thanks. I have an advanced question, maybe you can answer it... if larger grains are usually associated with weaker macro properties, how are single crystal turbine blades stronger than a blade made of many smaller crystals?
@@joshtargo6834 Great. Generally single crystal metals will have a lower yield strength than polycrystalline materials due to the absence of grain boundaries and their interactions with dislocations. However, single crystals have other properties which make them attractive in some applications such as anisotropic properties. One of the common examples of single crystals is in turbine blades, where single crystal metals are ideal since they have lower creep resistance, but they are generally expensive to manufacture. Single crystal silicon is ideal since it helps with the electrical properties.
Generally cold working/work hardening increases the number of dislocations as the plastic deformation causes the dislocations to interact with each other and multiply. The wiki page has a bit more of a deep dive into this en.wikipedia.org/wiki/Work_hardening
For someone whose native language is not English, who is studying mechanical engineering and is due to take a materials final, I find these videos incredibly helpful and am grateful I found them. Thank you very much for simplifying the issues in question. Greetings from Argentina!
Thanks for the comment and glad to hear they're helpful
Dr Wu, I started as a lab tech at a steel mill a month ago. I’m watching these and I understand my job so much better! Thanks!
Great to hear that the video was useful and best wishes for your new position
Exquisite delivery! Several centuries' worth of knowledge effectively and clearly disseminated in a few short lectures. I doff my hat for you Dr Wu. Thank you so much.
Thanks for the comments. Glad to hear it was useful and clear
i have my intro mat sci final tomorrow and you genuinely saved my ass...please continue to drop in those little logical explanations of yours they are very helpful in avoiding simple memorization
Glad to hear it helped. Hopefully learning the fundamentals will help to abstract the principles to other systems
Just watched the three videos on material science you have and WOW.
You explain just the fundamentals and very well, and everything makes sense.
Thank you so much for making these!
Thanks! Hope to make some more in the summer when I have some more time
A lot of people have already said it, but thank you very much again. You managed to fit two months of a semester or even more into 3 videos lasting just an hour in total. God bless teachers like you, who make the education accessible and easily understandable.
Thanks for the comment. Really appreciate it and glad it was helpful
This (paired with the first two videos) is an absolutely incredible introduction. I feel like i understand the heat treatment process 10000x better, wow.
Thanks. Glad to hear these videos have been helpful
Thanks a lot Dr. Wu. You have the best explanations on youtube. I don't generally understand this stuff but you made it so clear that even I was able to clearly understand it. You basically summarized my 2 hour lecture in 15 minutes. Would have loved to have you as my teacher. Once again thanks a lot and I wish you did more of these videos on other topics that would really help ......
Thanks Adam! That's great to hear
Thank you very much, this series of videos is most comprehensible content I ever seen on this topic.
Glad it was helpful!
Thanks a lot. I genuinely didn't know a thing about metallurgy and metals. But as I work closely with metal manufacturing I forced myself to understand the basic theory of how it is made. This video of yours explains so clearly the factors that affect the hardening of metals. I am so glad that professionals like you would share things that You've spent years to study and make it so easy to understand. really appreciate!
Glad to hear it helped
作为一名来自中国的学生的，我真心谢谢您，我一直被材料学所困扰，大学主要在于自学，您的解释与说明比我们老师要详细的多，请您持续更新下去，感谢！
Thanks
The three videos you have produced about phase diagrams, phases of steel, and this one are extremely well done. They are very easy to understand and I am grateful that you spent the time to put them together. Do you have a video on the bronze (Cu-Sn) phase diagram, or know of one?
Thanks! Appreciate the comment and glad to hear it helped. Unfortunately, I haven't got a video on Cu-Sn phase diagrams. Doing a quick search I can see there's a lot more going on in that specific system. The content out there seems mostly focused on research papers
Your way of explanation helps me to recall of what I studied from mechanical engineering.. especially your pronunciation easy to follow first non native English spoken person
Thanks. Glad to hear it was helpful
Dr. Wu.. Thank you. I'll be watching this video multiple times to better my gas turbine engine reports and the material run time damages they under go through out the engine's service life. I perform inter-stage inspections by video-scope and often wonder why certain materials and rotating parts have accelerated loss of strength and other areas and material types don't. It seems as if the single crystal process is the latest high temp, high tensile strength most tolerant in the engines I represent. Thanks for your time and mostly for simplifying the video.
Thanks. Glad to hear it was useful. Heat is one of the major factors which can influence the strength of a metal; impacting the grain structure and phase composition
Dr. Wu, Do you have capabilities to perform micro-structure tests on turbine blades?
Such a comprehensive review of this topic. Thank you!
Glad it was helpful!
top notch class amazing. Thanks brother!!
Great to hear it was useful!
Excellent video. I would like to include practical examples of the process for all three hardening techniques with constituents mentioned with weight or percentage to visualise the actual alloying process creating strength, ductility and resistance to corrosion
Thanks from Egypt
Glad you found it useful
Made so easy to understand the basics .. thank you sir😇🙏
Thanks. Glad it was useful
Thanks Billy Wu ....Your videos have been so helpful and gives lucid explanation. Thank you so much. I have one request. If you can make a video on Gibbs Free energy, it would be great.
Very high quality video, thank you
Thanks. Glad to hear it was useful
Sir. indeed an informative video, keep enlighten us. I request you to make some shots of TMT Bars (Primary and Secondary), and causes of failures. Thank you.
Thanks and glad to hear it was useful. Thanks for the suggestion for future videos. I have a list of potential next ones, but just need to find the time to create them
thank you so much Dr Billy, I am going to ace Material Science test.🥳
Glad to hear it was useful and best of luck with your exam
Dr Wu，Not Dr Billy
Incredible lecture!
Many thanks!
Thank you so much! The video is very clearly explained! It'd be great if you could post more videos on Material Science, cheers!
Thanks! Appreciate it and will try to get some more out
When cold worked via the milling process, what level of hardness could one expect for the outer shell of 303 stainless steel? Thank you for such an informative video.
Dr wu can you please explain to me why work hardening/cold working is defined as making grains smaller? To me, cold rolling elongates the grains, which by definition makes them bigger, or at the very least longer and post normalized recrystilization then allows new smaller equiaxed grains to nucleate. I only have a hnd in materials science, but I’ve worked in a steel mill for years as a metallurgist and this has always bothered me. I understand the area of the grains technically decreases but when you look at the steel under a microscope we always refer to cold formed steel as having larger grains and normalized steel as smaller more uniform grains. Seems to me as one of those things that’s different in theory than practical applications.
Great sir, Thank you so much for the best explanation, now we can say WOW
Thanks for the comments and glad to hear you found it useful
Hello Dr. Wu I have a requesting you to make video on Fe-C Diagram with your lecture where non metrologist can understand easily. Please it is my personal request to you. it helps me and others can get benefits on your lecture as always
Very helpful video, thanks a lot!!
Thanks! Glad you found it useful
Thx Dr Wu!
Mixing things up. Deformation in high temperatures and grain size evolution vs cold working. The Hall-Petch equation cited is only valid for ambient temperature !
Nice! Thanks man!
Thanks. Glad to hear it was useful! Your videos are exceptional too!
Good one, Useful
Thanks. Glad to hear it was useful
Thank you Doctor Wu for this very easy to understand video. I have one doubt regarding precipitated hardened stainless steel. We regularly use SS17-4 PH. The problem is the physical properties vary a lot after H950 for every part. We currently procure the material in Condition A (Solution annealed from 1042 °C), after doing the major boring/drilling/turning job, and then age harden it to H925 for 1 hour/25 mm cross section thickness (also acting as stress relieving). The problem is that we are getting elongation ranging from 8% to 15% and hardness from 34 to 43 HRC, which is too broad to categorise in any HT condition. Please suggest what should be the ideal way to process the material.
Thank you so.much for information
Thanks. Glad to hear you found it useful
a. It may be seen that the time to peak hardness and the peak hardness itself are a
function of the ageing temperature. Why does the curve at 30 °C not obey this
general trend ?
b. It may be seen that at the temperatures 110 and 130 °C an initial hardness plateau
occurs before the peak hardness is reached whereas this is not found at the other
temperatures.
i.
Why is such a plateau found at those two temperatures and not at the
higher temperatures?
ii.
Would you expect such a plateau also at 30 °C, although at longer
times?
help me with these questions
Amazing you are doing great
Thanks
吴博士，你太厉害了，献上我的膝盖
amazing, Thank you Sir
Thanks
Hi there professor I have another question here ,what type of alloys are suitable for precipitation hardening?
Usually alloys which have a composition where at room temperature they exist in a 2-phase solid region. Some examples might be aluminium, titanium and nickel alloys but there are many others. The key is that you can create this second phase to hinder atomic movements and strengthen the material
Hello, in the TTT-diagram, shouldn't the cooling lines be straight (temperature held stable) when entering the red pearlite part? Or is that not required? thanks!
Is there a way to prevent aluminium alloys overageing at room temperature? Or is it only specific alloys that will do this? Such as softer aluminiums?
Great question. The challenge with precipitation hardened alloys is that they are thermodynamically unstable and eventually will revert back to the thermodynamic composition and lose the strengthening benefits of the heat treatment (though this can be quite slow in some instances). Alternatively, dispersion strengthened alloys can also provide good strength by mixing in small particles of oxide materials into a metal matrix. The advantage here is that since the 2 phases are thermodynamically stable relative to each other you don't lose the strength at higher temperatures as precipitation hardened materials would.
Sir you are great
Thanks
Thank you sir
Glad to hear it was useful
Sir, how can we increase toughness in low alloy steel by heat treatment
I still have issues with learning this and a lot of material science parts
Idk why it feels hard for me to memorize
Any advice?
Supperb
Thanks
十五分钟视频拯救明天的final
what book did you get the TTT plot diagram from?
I adapted it from "Materials science and engineering" by William Callister. Fantastic foundational book for material science. Redrew it so that I can animate it so the exact positions might be slightly out but the core principles are the same
@@BillyWu Found it online, excellent. Thanks. I have an advanced question, maybe you can answer it... if larger grains are usually associated with weaker macro properties, how are single crystal turbine blades stronger than a blade made of many smaller crystals?
@@joshtargo6834 Great. Generally single crystal metals will have a lower yield strength than polycrystalline materials due to the absence of grain boundaries and their interactions with dislocations. However, single crystals have other properties which make them attractive in some applications such as anisotropic properties. One of the common examples of single crystals is in turbine blades, where single crystal metals are ideal since they have lower creep resistance, but they are generally expensive to manufacture. Single crystal silicon is ideal since it helps with the electrical properties.
Isn't work hardening reduce the number of dislocations, not increase it?
Generally cold working/work hardening increases the number of dislocations as the plastic deformation causes the dislocations to interact with each other and multiply. The wiki page has a bit more of a deep dive into this en.wikipedia.org/wiki/Work_hardening
@@BillyWu shouldn't the two interacting dislocations merge into one dislocation and thus reduce in number?
martensite is not FCC, but BCT
shoutout omar
12:10 ayo how do i go backwards in time. you didnt tell me i gotta be a timegod to be a blacksmith
please dont quench in water
Hey there Great upload! View our uploads and analysis on anything and everything Bollywood. I hope you'll like everything 😃🤘
ณ ? ฝททํ ไปดูบอล