§1. Introductions and how I teach [00:01]
I came back to MIT, and other than spending a year in Japan on sabbatical I've been here ever since — 44 years minus three. I worked for five years in industry in a big company. [Tom turns to a colleague at the front.] Tell them your name, Simone.
Belmar: Dr. Simone Belmar.
He's also teaching part of this course. Dr. Belmar did his thesis on fatigue and fracture, which is part of what he'll be lecturing on here.
Today is just an introductory lecture, and I teach this course in an unconventional MIT way. I don't like the way we teach our other courses. I have 41 years of experience here as both an undergraduate student and a faculty member, and I think that qualifies me to say I don't like the way MIT teaches, or any other college so far as that goes, particularly at the senior graduate student level. When I'm teaching freshmen or sophomores, I have to give them problem sets so I can grade them and distinguish whether they're an A student, a B student, or a C student. From my point of view it's a pain in the neck. It has no redeeming social value, particularly five years once you're out of school. You know how many times anyone's ever asked me what my undergraduate cume was? Once in 40 years. I've talked to other people and they said zero.
The only thing your undergraduate is good for is getting into the next school if you're going to graduate school. Your graduate is basically good for next to nothing other than getting out of graduate school. So for the last 25 years I've taught a course on welding and joining, which is what I got my tenure on, and then I switched over to more general manufacturing. I've only given out three grades: A's, F's, and incompletes. Don't worry about your grade, because it really is worthless. I would much rather teach older, more mature students who want to learn. And I'm not going to make you do lots of busy work, because I hated busy work as a student. I hated problem sets — I thought they were a total waste of time. They were completely contrived.
Think about it. A problem set — the professors always give you just the right amount of information, no more and no less. Twenty-five years ago I was teaching sophomores thermodynamics, and I started giving them either too much information or not enough information, and the students went berserk. You got to come to MIT because you learned how to take all the pieces of the puzzle and make the problem work — everyone gave you a full deck, no more no less. When I threw the students a curve by giving them more or less, they didn't know how to solve the problem. At that point I decided there's something wrong with problem sets. That's not the real world. Your boss doesn't give you all the pieces of a problem and say go solve this. In fact your boss may give you a problem, and if you're a materials engineer, he may give you a civil engineering problem, or an accounting problem, and guess what, you have to go solve that problem.
When I was department head I used to teach the sophomores in the department how to find a job. Does anybody know why someone hires you? Give me a sound bite on why someone would hire you. Someone hires you because they think you will help them solve their problems. They're not hiring you because they think it's a good thing to do for social welfare to give you a paycheck every week. They're willing to part with some of their hard-earned cash because they have problems and they want you to contribute. The corollary is: you never bring a problem to your boss, you only bring solutions. You may not know what the solution is, but you're MIT students, you ought to be able to figure out two or three good solutions, and if you're smart you'll present all three to your boss in the proper order so that only an idiot wouldn't choose the right one. This is how you manage your boss.
§2. What MIT does to its students [05:31]
Those are the types of things you need to think about in your education. Frankly, I'm not interested in math. I've sat in faculty meetings for 35 years, and as recently as two weeks ago I sat in a faculty meeting where the faculty were complaining that the students aren't good enough in math. I've always said, are you kidding me — half the MIT undergraduates got 800s on their math achievement test. I thought I was a big deal when I came here. I was the only student in my high school who got an 800 on anything — I got an 800 on my math SAT, only student in my high school in Virginia Beach who got 800 on anything. I came to MIT and the first day over in Kresge Auditorium they showed us a profile of the class, and I found that a third of my class had 800s. That sort of put me in my place. I very quickly learned that although you were great in high school, and you learn to compare yourself with others on academics because you would win most of the time, when you come to MIT, on average you're average. You have to learn a whole new way of thinking.
So a few years ago I took 30-some years of MIT experience and wrote an article for the faculty newsletter. The reason I wrote it: I didn't want Bob Brown, who was Provost and former dean of engineering, head of chemical engineering — we had served on engineering council together — I did not want him to become president of MIT. He's now president of Boston University. When he left MIT he didn't get president; Susan Hockfield was selected. When Bob left to become president of Boston University I sent him an email saying bye jerk. Boston University's loss was our gain.
I wrote this article on leadership, management, and education at MIT, which was the result of 12 years of thinking after I'd been here for 20-some years. In the early 1990s I started thinking, what makes MIT unique? There's a number of things that make MIT unique, and I wrote this article about it. I also talked about the difference between leaders and managers. One of the things I learned back in the late '80s when I took a Sloan program for senior executives at the Sloan school was that you have to learn to communicate, and to communicate in this world you have to speak in sound bites. Some people talk the elevator talk too long; you have to do sound bites. The sound bite for leadership and management that I came up with: a leader seeks to help others, a manager seeks to control others. Now I can pick out in the first couple of minutes of a meeting whether this person is a control freak and therefore a manager, or whether this person is actually there to be helpful. As a result I'm now completely cynical about the leadership of MIT, which is composed of a bunch of managers who want to control people.
This has not much to do with materials processing. But I'd rather talk about some of those things, because I actually look at the courses I teach not as a course in welding or joining or sheet metal forming or casting, but to try to tell you stories you will remember, and also to give you a few ideas of things I've learned over 40 years at MIT that I wish someone had told me when I was your age. Not you, Carl — your age is closer to mine now. I wish people had told me why someone hires you: because they want you to help them solve a problem. If you have those fundamental principles you'll know you're smart enough, in spite of what MIT teaches you, that you're stupid. That's part of my article.
One of the things we tell the students is they're average or below average. Well, you're not. Go out there in the real world and very quickly you relearn that you're above average. Anybody experienced that yet? Learning that MIT told you you were stupid and then going out in the real world and finding you're not necessarily more stupid than anyone else — in fact you might even be smarter than some of the other people, and you will actually be successful someday. One of the problems of this place is that the people who graduate from MIT have less self-esteem than the people who entered MIT, and they're the same people just four years apart. I consider that to be one of the great disservices of an MIT education, to teach you that you are not as good as you really are. One of the great services of the MIT education is to teach you humility — and that's actually teaching the same thing. So one of the great disservices is also one of the great services. That's in the article. You can read it. You won't be quizzed on it, except every day of your life. No one's going to grade you on it.
§3. The modular course structure [11:03]
What is this course about? It started when I got back from my sabbatical in Japan in 1985. I had gotten tenure and now had the right to teach my research subject, which was welding and joining. I taught it mostly the traditional MIT way. Then six or seven years later we started the program called Leaders for Manufacturing — now Leaders for Global Operations — joint with the Sloan school. I started focusing more not just on welding and joining but manufacturing in general. I have always worked a lot with industry, more than the average MIT faculty, so I had stories to tell, and that's what students always talk about when they talk about my courses. They remember the stories. So you're going to hear some stories today, and every day that I'm lecturing.
About a year and a half ago, Chris Schuh — now the department head, but at the time chairman of the graduate committee — came to me and said, Tom, the department wants you to have more face time with the students, and we want you to teach more than just welding and joining. We want you to teach solidification, and whatever you want — we need more courses in metallurgy and materials processing. I said okay, but the only way I can do this is in my approach. I'm just as busy as you are, and my schedule is not nice and easy Monday Wednesday Friday at 9:00 or Tuesdays and Thursdays at 11:00. What I had been doing for years with my welding course is teach it every single day I was in town, and in the fall we'd finish by Halloween. That's what we're going to do here.
I'm going to teach a third of this course live. Dr. Belmar is going to teach a third of this course live. You're going to watch another third by video of me lecturing last summer to a bunch of Navy officers who were here in course 2N at MIT. The first module, which is probably the last one you'll do, is basically an introduction to materials processing. Jeremy in the back with the video camera is actually taking the course just like you, but he's earning a little money on the side because he's going to be here videotaping for the future. It'll be three years before I teach this third again. I'll warn you that it's been 30 years since I taught this subject of deformation processing. And the book I learned from, the book I taught from 30-some years ago, is out of print.
Dr. Belmar is going to teach you about structural life assessment. Really I'm supposed to be teaching an introduction to materials processing, but the introduction I teach is structural materials. If you're a civil engineer you're probably not interested in how to make a semiconductor chip — neither am I. If you're a nuclear engineer, you may be interested in semiconductor chips but you may not care about how they're made. Civil engineers might be interested in using them but you're probably more interested in structural materials. You might be interested in corrosion, you might be interested in welding. My goal is to come up with about nine or ten modules that students can take three at a time. If nobody wants to come to class this semester but you want to get credit, you could take three of the four modules that already exist.
The four that already exist: one is the intro to materials processing and a descriptive thing on casting of metals — the one I put together last summer when Professor Schuh asked. Another is joining technology, which I've been teaching some version of for 25 years. The next is fusion welding, also about 25 years. The other is a mishmash of material selection, non-destructive testing — NDT — and welding mechanics. Each of these modules is about 12 or 13 hours of lectures, hour being a 50-minute hour.
These two modules go back 25 years and have been modified — more stories than I used to have. This one started about 15 years ago when Professor Masubuchi retired. The Navy students had certain things like welding metallurgy that I wasn't covering because he had covered it for 25 years. When he retired, the Naval Sea Systems Command wanted them to learn welding metallurgy. They said, will you add that? I said, well, the students need to learn about material selection, so I'm going to teach material selection. No one around here tells you how to go out and test something — x-ray, magnetic particle — so these Navy guys need to know what's going on because they use it every day. I added that, the welding metallurgy they wanted, and fracture mechanics. I've never thought fracture mechanics is a typical MIT subject where they teach you all the theory and never any of the practical use of the product.
§4. The Defense Materials Research report and the cost of weight [17:54]
[Tom passes around a report.] This handout, Materials Research Needs for the 21st Century Defense Needs — I served on a committee of the National Research Council around 2000 or 2002. We were supposed to look at how the Defense Department was going to figure out what they needed to do in materials research for the next 20 or 25 years. I had some unconventional things, so I wrote up my chapter and they decided it was so useless they made it Appendix C, because it didn't fit with everything else in the report. This is about 10 years of my thinking about what really controls material selection.
Let me tell you an anecdote. A year or two before me, Professor Joel Clark became a faculty member in this department. Joel was unique at the time — nearly 40 years ago — in that he had both a PhD from this department, where he'd studied the structure of magnesium-cadmium alloys (what use is that?), but also an MBA from the Sloan school. He was hired to look at the economics of materials and material substitution. Forty years ago that wasn't a hot topic. Joel was hired to pioneer that area, and he has. About 20 years ago I was walking across campus and met up with another faculty member, very prominent in the department, full professor now, but a young faculty member at the time. He said, did you see Professor Clark's article in the Journal of Metals? I said yeah. He said, well, I never thought about it before, but cost really is important, isn't it? This is a rocket-scientist MIT professor who had just learned. Now this person is worth tens of millions of dollars and has started one of the most successful companies in the department, and I bet you he's learned more about the importance of cost. But at the time this was a great revelation to him.
If you want to know something about material selection — and this is in the module I'm proposing all of you watch on video — I give you one of the keys. Does anybody know what the value of a pound of weight saved in an automobile is? It's about $2 a pound over the life of the vehicle. If you can take a pound out of the car over the next 100,000 miles, you'll save $2 in gasoline. Some people argue it's $2.50; who cares. Anybody know what it is for an airplane, if you're Boeing? $200, very good. Have you heard this before? Last semester, okay, you should have. Anybody know what it is for a spacecraft? $20,000 a pound is about what it costs to get up into orbit.
The space shuttle in the late 1960s was supposed to lower the price of a payload into orbit from $10,000 a pound to $1,000 a pound. How successful was the space shuttle? Well, it upped the price to about $300,000 a pound, because it had a few problems — but that's another story. It didn't meet its goal. Then there was the X-33 space plane that was supposed to give us a reusable space shuttle, and it had problems too. We'll tell you some of those stories in some of these other lectures. But you have to decide which modules you want to take.
§5. Deformation processing, Backofen, and the rediscovery of superplasticity [22:29]
I'm going to give one on deformation processing — extrusion and forging and sheet metal forming and wire drawing and coining. Deformation Processing is what Al Backofen called it. Al was the faculty member in the department, the first person I worked for as a sophomore. He wrote this book, and I took his course. He had been teaching it for probably 15 or 20 years, and I took it about the time the book came out, in 1972 or so. He didn't have a clue what he was talking about when I took the course, just like you don't have a clue what most people — I've taken courses too. I started to learn it the first few years as a faculty member, when I was teaching out of that book. I have gone back to that book about every two months for the last 40 years for some of the concepts in it.
There's another professor who taught solidification, and I actually helped edit his book before it came out. Deformation Processing is out of print. You can buy it on Amazon used for about $80. The other professor's solidification book is also out of print — you can buy it on Amazon for $800. I didn't pull that solidification book off the shelf until last summer when I was teaching solidification. That's how useful I found the concepts. But this book on deformation processing has really helped me on a semi-monthly basis over the last 40 years.
Fortunately, there's a guy named Bill Hosford who was one of Backofen's students back in the '60s, did a PhD with him. He went off to Michigan, became a professor, and wrote a book called Metal Forming. It's not as broad as deformation processing, and it's a little easier to understand, actually, because Backofen is so dense. Backofen required his PhD students to condense their thesis down to 30 pages. It would typically take the student after they finished all their research another year to finish condensing the ideas. They'd come in and present the hundred-page thing — and this is before word processors, folks — where they had it all typed up and gave it to him, and a couple days later he would curse them and throw the manuscript at them and tell them get out of here until they came back and wrote something decent. That was the advice he gave to his students: come back when you've written something decent. He wasn't loved by many of his doctoral students. In fact he was hated by most of them. But by forcing them to condense things down to their essence, that book is the densest book I've ever read on engineering. There are more concepts in there, but I'm not going to make you learn from that.
We have Bill Hosford fourth edition — actually third edition — 2007 copyright. He's added two chapters to the fourth edition. The principles haven't changed that much. $6.95 on Amazon a month ago, until I bought enough copies they raised the price to $15. But I bought enough that you all get a present from me. Here's your third edition copy. Fire sale. What happened was, good old Bill Hosford in his retirement is pumping out extra editions, so they overprinted the third edition, and you now have a textbook. If you publish a book, don't surprise your publisher by coming out with another edition four years later just because you want to make money. Amazon wouldn't let us order more than nine at a time, but we put in three or four orders. Did everyone get one? Anyone not have one?
We will use Hosford's book in place of Backofen's book, but I want you to know what I'm really going to be working from is Backofen's book. You don't need to buy it because you're not going to be quizzed on it. I'll also be working from some other books — here's one by Taylan Altan, professor at Ohio State, on cold and hot forging. Here's one by someone from Italy on superplastic forming.
Anybody from the aerospace industry know anything about superplastic forming? We couldn't build jet engines today unless we had superplastic forming. Who discovered superplastic forming? Superplasticity was discovered — some people say, if you read that book, people had discovered this process back around 1900. They take a tensile specimen. Anybody know how much elongation you get in a tensile specimen when you pull it, approximately, a piece of steel? Take a guess. A few percent? 30%, typical elongation. A fairly brittle material is less than 5% — you don't like to design structural things with less than 5% ductility, you like more than 10%. Average steel is 30%, really good steel, really clean steel, 40%. Superplasticity — we'll talk about 400%.
What was happening: Professor Backofen in the '60s was looking at the effects of fine grain size. Professor Grant was looking at the effects of no grain size, or very large grains, because he was a high-temperature materials person. He was the person looking at things like turbine blades for jet engines. [Tom holds up a turbine blade.] This turbine blade goes back 20 years. It's a single crystal, no grain boundaries. Grain boundaries destroy the creep high-temperature properties. The grain boundaries are like butter and the thing just slides and deforms. If this was a good blade it would be worth about $6,000 or $7,000, and there's a hundred of them on every wheel of every turbine engine. That's why the engines cost five or ten million bucks. Grant was looking at how to get rid of grain boundaries in structural materials for high-temperature properties. Backofen was going in the opposite direction, looking at how to get very fine grain size, and how things deformed. We'll talk about that.
Backofen rediscovered superplasticity. He found a 1938 paper from Germany where they had measured superplasticity with very fine grain material. Because of World War II it got lost. It wasn't until the early '60s that Backofen rediscovered it. I will bring in some of Backofen's original samples — I was, you know, the short little door 8137 as you walk down around the corner from the infinite corridor, that was my first office. I shared it as an assistant professor with Backofen's last doctoral students, and I picked up many of his samples. When I teach deformation processing, you're going to see Al Backofen's samples, his touchy-feelies, to pass around the room. These superplasticity samples should be in the Smithsonian. We couldn't build jet engines without superplasticity.
Invented — not invented here at MIT, invented in Germany, but everyone forgot about it because they had this little war, and Backofen reintroduced it. Backofen was a genius, but he was also sort of a social jerk. Throw the manuscripts at the doctoral students, yell at them, curse out his contract monitors in Washington and wonder why he couldn't get any research money the next year. But he's an interesting guy. There are good stories about Al — we won't go through those now.
§6. Schedule, presentations, and picking a part [31:37]
The three modules right now are intro to materials processing and casting; Simone will do life assessment; and I will do sheet metal forming, deformation processing. Your assignment for this course: if we meet five days a week, Monday Wednesday and Friday in 4-145 at 9:00, that's when we're supposed to have lectures. If we meet up here Tuesdays and Thursdays, and we meet five days a week, you don't have a lot of reading. You can read these things I've handed out, but you're not going to be quizzed on them; you don't want to read them, you don't have to.
In the meantime, you will have to do something, because MIT requires that I do something to evaluate each student individually. It's in the rules of the faculty. So you will have to give a presentation in this course. This is your first assignment — you have to hand this paper back in, you can scan it and email it to us if you want — you have to tell us about a part you're going to make a presentation on. We're going to have two presentations a day. For the first half of the term you're going to come every day and you're going to see Tom Eagar or Simone Belmar, or you're going to watch a video.
This week I'll tell you the schedule. I'm giving intro to the whole course today. Tomorrow Dr. Belmar is going to start her first lecture on life assessment. Wednesday you're going to watch the intro lecture. Last summer I was supposed to talk about casting, and I thought, well, everything anyone talks about now is nanotechnology. How many people in materials are working on nanotechnology? Nobody. Maybe that's why. How many of your colleagues are? 80% of them, right? I went to review 24 NSF proposals a couple years ago and my comment at the end of the day was, at least I learned how to spell nano by reading these 24 proposals. I am a little cynical.
On Thursday you'll get the intro lecture. I will tell you why, from basic physics, kinetic theory of gases, people start to make structural materials with castings, from liquid metal and not from the vapor phase. The real reason is, when you cast something you can process it at least 100 million times faster than if you produce it from the vapor phase. In the vapor phase you can grow something at about, if you're lucky, a millimeter an hour. How many people would like to build a bridge across the Charles by building up the steel at a millimeter an hour? Really good idea, at a price of $10,000 a pound. Who wants to pay $10,000 a pound to rebuild the Mass Ave bridge? Guess what, they use steel. There's a reason for it.
When I was a student they taught steel mills. My first job as a TA in graduate school, second term senior year, was for a course taught by Tom King, former department head, who is a blast furnace metallurgist, came out of Scotland, the University of Strathclyde. And Keith Johnson, who was a quantum mechanics, ab initio type modeler guy before all the other ab initio modelers — this materials chemistry senior course went from blast furnace chemistry to quantum mechanics all in one course, broadest course you've ever seen, and I was the TA for that. Nowhere but MIT would you include blast furnaces and quantum mechanics in the same course, but we did. That's the beauty of the modular method of teaching.
Most of you should take the introduction module and listen to my introduction about why nanotechnology is great for functional materials but not so great for structural materials, and then it'll go through different casting technologies. How might you make a class ring — but how can you make something with a lot of detail? If the Patriots had won the Super Bowl they would have gotten a Super Bowl ring. Now the Giants get one. Those will be produced this summer down in Attleboro, Massachusetts. They may have to design them first, but they will be produced by lost-wax casting.
On Friday — I have to go see the eye doctor, so Dr. Belmar is going to lecture Wednesday and Friday. Next week I'll probably take Monday Tuesday Wednesday, and he'll take Thursdays and Fridays in this room. At least that's the schedule for the next two weeks. Any questions on schedule? Just come every day, forget whether it's recitation or lecture, it's going to be one of us or it's going to be Jeremy showing you a video.
Student: If we're interested in taking one of the pre-recorded modules instead of a live one—
You're welcome to do that, just come talk to my secretary Jerry Hill. If you were interested in three of the four pre-recorded modules, you wouldn't even have to come to class. You don't have to listen to me rant and rave — well, at least not live; you'd watch me rant and rave on video. You can get credit for the course by taking three modules, your choice. My suggestion, since if it's live you can interrupt me and ask questions — and I actually do want you to interrupt and ask questions, because I would much rather digress and tell a story based on your question than go through whatever mess I was prepared to talk about. You'll get to see that as you see me lecture.
§7. The part assignment — wedding rings and the price of platinum [38:39]
You're not going to be quizzed on any of this stuff anyway. The requirement is you must tell us whether you're going to emphasize a production methodology for making a part, or you're going to do a life assessment for a part, or you're going to actually do both. You're going to pick a physical object. What do we mean by a physical object? You could pick a wedding ring, or just a circular ring, a simple ring. You could take a complex class ring. I would suggest you keep things fairly simple. You'll have to tell me — if I talk about a wedding ring, let's say a simple band, what are the potential materials of construction? Come on, some of you have them. What are they made out of?
Students: Silver. Platinum. Gold. Sometimes steel.
Silver, platinum, gold, sometimes steel — in the worst case. My middle son has a titanium wedding band. We could talk about why titanium is good or bad for wedding bands. Other ideas? In some societies all they can afford is a steel band.
If you're going to make a million steel bands — they don't have to be wedding rings — I know an organization that for seven-year-olds gives out a little ring with CTR on it, which means "choose the right." You try to tell the children they're supposed to choose the right rather than choose the wrong. You don't tell that to people your age because you say, oh duh. Well, then why do you choose the wrong sometimes? That's another philosophical thing. But seven-year-olds you can teach to choose the right. They want to make these inexpensively, with this little embossing. They make it as a strip and each child wraps it around their finger; it's soft enough that they don't have to size it. Self-sizing. So you could take something like a simple ring.
You get to pick what it is and you can pick it out of your own experience. You worked on a nuclear reactor — you're going to make a valve? That's probably a little too complex; take something simple like a washer that goes in a nuclear reactor. How would you make it and what material? Pick your object. If you have a problem, come see me — make an appointment, come by, I'm usually in by 7:00 in the morning. Don't get a lot of students coming at 7, but anyway. Figure out the materials. If you do wedding bands you might say, okay, I'm going to look at the whole gamut from steel to copper to brass to titanium to silver to gold.
Anybody know — just like we talked about, the price differential of a pound of weight in a car is $2 and a spacecraft is $20,000 — anybody know what the approximate ratio of the cost of a pound of silver to a pound of copper is? It's about 100. Same type of ratio. Anybody know the ratio of silver to gold in cost per pound? About a factor of 100, which means gold typically costs 10,000 times the price of copper. So there's a difference between gold bands and silver bands and titanium bands. Now people use platinum. A pound of platinum or gold is closer to $15,000 or $20,000 a pound — it's about $1,000 to $1,500 an ounce, somewhere in there. When you get to that, it's a whole different manufacturing game.
I worked for about 10 or 15 years with the largest manufacturer of gold jewelry in the world, down in Attleboro. They go through seven tons of gold every year. They cast it and form it and shape it, and you're going to hear some of my stories that come out of that plant. They had an inventory shortfall once, and my consulting project died with them in the early '90s. But just recently another company down in that area, the second-largest jeweler in the world, came and said they want to do some work with MIT. I went through their plant two weeks ago and they make a lot of platinum rings.
Do you know how they make a platinum wedding ring? They start with a thick-walled platinum tube and they slice it, and they take those slices and put them in an automatic screw machine and turn them down to make little circular platinum bands. They used to cut them mechanically in that lathe, and they had a kerf that was about 8/10 of a millimeter, 1/32nd of an inch. A kerf is the width of the cut. That's a lot of scrap when you're dealing with platinum. In that industry — and I learned this 30-some years ago — the cost of processing is insignificant to the carrying cost of the interest charge: you're putting the product out the door from the gold bullion or the platinum bar that comes in, and getting it out as a finished product. If you can do that within 48 hours, not within two weeks — you want to do it two days, and you don't care what it costs to process it. That's different than most industries, but the value of the product at $22,000 a pound as raw material cost means you need to get it out of there quickly.
They switched, and they came in with a high-power laser, and they take these tubes and slice them up with a high-power laser. It's a three- or four-million-dollar laser; payback was two months. Now they catch the platinum vapor and recycle it. But the kerf is one-quarter as much — they save three-quarters of the kerf, and they paid for a multi-million-dollar machine in two months. Production volume and materials of construction interact. If I'm going to make wedding bands I can make a million at a time, or I could make one that's unique.
I made my wife's engagement ring. I electron-beam-melted it over on the fourth floor of Building 8 with an old radar power supply, almost electrocuted myself. That's another story. My wife didn't know that until after we were married — I electron-beam-melted it out of platinum-iridium. Telling this story earlier this morning — Mike Tanyon made layers of sterling silver and silver, diffusion-bonded them or laminated them together in the furnace, rolled it and twisted it, then machined part of it and made his wedding band. There are different ways to do it. Ours are unique, one-of-a-kind wedding bands, simple objects.
§8. The hammer and life assessment [46:23]
There are other simple objects. Let's say instead of how you're going to make it, you want to talk about the life assessment. Maybe you want to take something like a hammer. [Tom produces a hammer.] There's a question of materials of construction. You want a head that is hard so it can drive a nail, but not so hard that it's brittle and doesn't bend if you overload it. You might want to make it out of a copper alloy. Anybody know why they use tools made out of copper alloys, beryllium copper specifically, because it's the hardest copper alloy, about 200,000 PSI yield? Anybody know where they use them? There's one industry —
Student: Non-sparking.
Non-sparking, exactly. What industry?
Student: Coal mining.
Coal mining, where you're surrounded by methane gas and the last thing you want is someone to hit the shovel against something and have steel against steel and a spark, and everybody goes boom down at the bottom of the mine. All the tools in a coal mine are going to be beryllium copper.
You can make them with plastic handles. I went over to the lab to get this and what did I find? Out of the toolbox this one's defective and it's not going back to the toolbox — someone should have thrown this one out. The plastic has cracked, but other than that it was fine. High-mass head up here, plastic handle. You can do a life assessment. You can look at failure modes effects analysis. If you're interested in structural life assessment, pick a product, something simple like a hammer — don't pick an automobile because you can't do a 15-minute presentation, which is what you'll have to do after spring break. We're going to schedule two students a day.
You know what I forgot to do — you should sign up. There are two of these sheets so I know who's going to be here. Pick a simple topic, a very simple thing like a simple ring, or something simple like a hammer or a garden rake, I don't care. Take something simple because as you get into it, it's more complex than you think right now. By February 29th, pick something, fill out this sheet, sign it, give it to us, we'll approve it or not approve it. I probably won't approve it if you tell me you're going to build a space shuttle — a little complex.
I would encourage you to keep it simple. Then you'll have a whole month or six weeks to come up with a 10- or 15-minute presentation. It can be in PowerPoint — I can tell you what I think about the evils of PowerPoint. I have a nice article that gives you the Gettysburg Address using AutoCAD — or Auto Content Wizard in PowerPoint — you can take one of the great pieces of English literature and turn it into pure pap with Auto Content Wizard. Properly used, PowerPoint is just fine. Improperly used it's a joke.
§9. Why imperfections control strength — carbon nanotubes and iron whiskers [49:50]
Anybody have any questions? I've been rambling about a number of things and you did hear a couple of stories. You'll hear more stories in most cases. You have to decide which three modules you want to take. My suggestion for the average person here is to take this video, listen to the structural life with fatigue and fracture mechanics. Dr. Belmar reviewed at my suggestion this book on structural life assessment, written by a guy from the aerospace industry in Southern California, so it has an aerospace bent. But fundamentals of fracture mechanics, fracture phenomena, fatigue crack life assessment and improvement methods — it's really a damage tolerance text. If you're in the nuclear business, you ought to know some of this stuff: what size flaws are harmful, environmentally assisted crack growth, corrosion, fracture mechanics, and application. He's not going to be teaching directly from this book like I'll be doing from Hosford, but he will be covering fatigue and fracture of materials.
And why imperfections control the strength of materials. Anyone ever heard that bucky balls and nano graphene and stuff are super strong? Absolute garbage. A physicist's pipe dream. I can take a sheet of paper — you'll see me doing this on the History Channel when I talk about the Titanic — and pull on that piece of paper with pounds of force. But if I put a flaw in, that takes ounces. The inherent strength of a material may be millions of PSI, and you can do the calculation. I do it in the joining lectures. A carbon nanotube should have two or three million PSI strength. That's only true if you don't have a vacancy. If you have an atomic vacancy, then it's just like having a defect. If you really made a real carbon nanotube, it would fail at 1/10 the theoretical strength.
We've known that for 50 years. The physicists didn't know it because they were 50 years behind the materials scientists — actually they're still more than 50 years behind. We grew iron whiskers in the 1950s that were a single crystal, all but a screw dislocation up the axis. They pulled those and got 2 million PSI strength experimentally, because if you don't have any mobile dislocations, you pull on a screw dislocation parallel with the axis of the screw dislocation, it won't move. It was like pulling a perfect crystal, and they got 2 million PSI strength for steel. We don't have steels at 2 million PSI. But the physicists are out there telling Congress and everybody else in the world that they've discovered carbon nanotubes that will allow us to build the rope chain to the moon. You've heard about that, haven't you? Some of you saying yes.
They say they can do those carbon nanotubes. I'm going to let Jack climb that beanstalk first. Because I know that if you have a vacancy — and if you're a materials scientist you know that at any temperature above absolute zero you will have vacancies in the material. You can prove that, second law of thermodynamics. You will have a mixture of atoms and vacancies at any temperature above absolute zero. So the physicists are getting billions of dollars to study carbon nanotubes, and it's just money down a rat hole. They might be good for display technologies and other functional materials, but for structural materials, don't invest. Any questions? In the future I want you to stop me and ask questions.