Alright materials science geniuses, design a High School level metallurgy class!

[neutrino_cannon]

One of the things that strikes me about the society we live in, even in this age of synthetics, is how many things are made out of metal. I recall one writer who marveled on the stupendous number of inventions that require springs, and how fortunate it is, therefore, that springs are some of the more predictable, versatile and reliable machines in the world. Cars, another ubiquitous invention, are made of metal. Large buildings are made of metal-reinforced concrete. Products are advertised with the names of metals (gold-level cards, titanium-edition razors). Clearly, some understanding of metals is more than a passing academic curiosity.

In addition to blighting a complete understanding of the world, I feel also that the current high-school level of understanding of metallurgy and materials science is sufficiently poor that it also keeps many otherwise promising students out of trade schools. There will be plenty of demand for welders in the foreseeable future, and I certainly think it preferable that someone who could become a welder rather than a burger flipper. If they haven't the foggiest notion of how all that sort of thing works, why would they pursue it?

I, of course, have a stellar understanding of materials science. There several types of strength, like tensile strength, and also all those other kinds. Also, alloying two different metals doesn't average their properties. It's sort of weird and random, like how you can add a little bit of carbon to iron and get steel, and how you can put a little bit of copper in aluminum and make duralumin. Also, oh hell, I hardly know anything about this! See how poorly our educational system has prepared me for life in an iron society?

So, your mission, should you choose to accept it, is to design a high-school level metallurgy class. What lessons will be taught? How will you keep the lesson accessible to less educated students who probably won't be going to college? How will you integrate the lessons into the school system? Part of shop classes or sciences? How do you pitch the idea to administrators so that someone else gets axed when the budget fluctuates?

[Michelle Lyon]

Question. Does the high school have an ROP program? Can the class be taught through this program, rather than through shop?

[X]

Start with the basics: material properties.

Stress
Strain
Strength
Stiffness
Hardness
Elasticity
Tension
Compression
Hooke's Law
Deformation


Some apply to stress analysis as well, but all are fundamental to material science.
Then, once the basics are understood, you can progress to things like strain hardening, ductility, brittleness, temperature effects, and the like.

[AgeGap]

When I was at school the class was taken out to a local technical college. We were taken to a material sciences lab where we watched metal bars and rods get tested for things like hardness. Also watched bars under strain getting puled apart. Every time the broken bars showed a classic cup and cone fracture. This was over twenty years ago so it has obviously left an impression. In part due to Uri Gellers claim that the fracture obtained when he bends spoon is unlike others seen in the real world.

[Sunstealer]

What age group are you aiming it at within "high school"? 11-16, 16-18? I ask this because they do need to understand some basic chemistry and physics (which also means mathematics) before they start. You can start with the basics as suggested by [X]. I'd probably chuck in a bit of crystallography too and certainly do some metallography/property testing within the context of material properties, because it's practical and all children like looking down microscopes. Arrange for them to go to a lab/university to see how it's done.

Personally I think that a huge part of the theoretical side of things is far too complex for pre 16/18 so going for a broad and practical approach is best. You can't teach the subject only give them a flavour for what it's about. So perhaps take the manufacture of steel and some of it's uses as the example. From ore to finished product say a kitchen knife. (My favourite would be the katana - samurai sword). This will give a good opportunity to explore extraction, blast furnace, basic oxygen furnace/oxygen blowing, casting, forging, heat-treatment and what alloying can do even in very small quantities to give all the required properties as shown by [X]. Even a trip to a blacksmiths can be used to teach the science. A good way to get children involved in making something.

[GreyICE]

Originally Posted by neutrino_cannon

One of the things that strikes me about the society we live in, even in this age of synthetics, is how many things are made out of metal. I recall one writer who marveled on the stupendous number of inventions that require springs, and how fortunate it is, therefore, that springs are some of the more predictable, versatile and reliable machines in the world. Cars, another ubiquitous invention, are made of metal. Large buildings are made of metal-reinforced concrete. Products are advertised with the names of metals (gold-level cards, titanium-edition razors). Clearly, some understanding of metals is more than a passing academic curiosity.

I just feel I have to comment on this.

Springs are used because they are predictable, versatile, and reliable. If they weren't, we'd use something else (for instance piston-cylinders full of air replicate many/most of the properties of springs very easily).

It is not fortunate that springs have those properties. The inventions use springs because they have those properties. It's the good ol' puddle marveling at the hole that exactly fits it.

[The Man]

I was taking a mechanical technology AAS curriculum in the1980’s, with the intent of becoming a mechanical designer and engineer. The curriculum included a two semester course on metallurgy, the primary reason I was taking that curriculum. After completing the first semester of core courses (applicable to the other two AAS technical degree programs as well) they discontinued the mechanical technology curriculum. As a result I went on to obtain both of the other AAS technical degrees, Electro-mechanical Technology and Electrical Technology. Ironically, I worked the next 18 years in mechanical design and engineering, finally working my way up to an engineering position (as well as Project Engineer and Production Engineer). It is only now that I am working as an Electro-mechanical technical consultant (and making more money). Even collage based metallurgy courses were starting to fade away back in the 80’s

Originally Posted by [X

;3736587]

Start with the basics: material properties.

Stress
Strain
Strength
Stiffness
Hardness
Elasticity
Tension
Compression
Hooke's Law
Deformation


Some apply to stress analysis as well, but all are fundamental to material science.
Then, once the basics are understood, you can progress to things like strain hardening, ductility, brittleness, temperature effects, and the like.

I think [X] has pretty well covered the basics here and that in it self might even be a bit much for a High school Material Science curriculum, before even getting to the specifics of metallurgy. In the machining part of the Electro-mechanical curriculum we did touch a bit on metallurgy, but I learned far more by actually working in the field of mechanical design and engineering (as well as doing the machining and welding, often required, myself).

I think the best way to get High School students interested in such things would be through the metal shop and auto shop courses that one might tie in with popular shows like “Orange County Choppers” and “Monster Garage”. As far as dedicated metallurgy courses, I just do not think you could sell that in this day and age at a pre collage level (and might have some difficulty even at a collage level). It is just a sad aspect of our times. Just about every high school kid wants to own the custom cars and bikes they see on TV and might even want to build them, but few want to learn the real engineering and design that we need to build everything (including custom cars and bikes).

[jj]

The problem is having access to equipment, and being able to ensure "safety" in this day and age of fear-of-everything.

What comes to my mind when you say "metalurgy" are things like:

Giant machines that exert pressure.

Hot crucibles with molten metal in them.

Hot furnaces from which you plunge hot iron into cold oil, making short-term flames.

etc.

Heck, I'm an old guy and I'd want to take the class just for the (*&*( of it.

[The Man]

Originally Posted by jj

The problem is having access to equipment, and being able to ensure "safety" in this day and age of fear-of-everything. .

Exactly, exposure is the key element, more to the limited available equipment then the lack of safety (or perhaps as you remark, both).

Originally Posted by jj

What comes to my mind when you say "metalurgy" are things like:

Giant machines that exert pressure.

Hot crucibles with molten metal in them.

Hot furnaces from which you plunge hot iron into cold oil, making short-term flames.

etc. .

Three sentences (less the ect..) resulting in an accurate production and testing description of metallurgy.

Originally Posted by jj

Heck, I'm an old guy and I'd want to take the class just for the (*&*( of it.

Heck, I am probably a “not so old as you guy”, having been in the field of metal material engineering and I would take the class, if I could find and afford it. The problem is how do we convince the “much less older then us guys or girls” that it is something worthwhile.

[JoeEllison]

It could be a good time. If you could get mounted samples of steel at various stages of hardening and tempering, that could be fun. You know, show the kids austenite and martensite, carburization and decarburization.

[Terry]

Could you have a teacher cast a bunch of small zinc ingots, cut them in half, and have the students polish and etch them to see the grain pattern? I guess having the students cast them is out of the question in this day and age...

[jj]

I think we ought to have a high-school class on swordmaking. From casting the blank to working it (with modern hammers, etc), to sharpening it.

What say?

You could choose, modern vanadium tool steel or do your own Damascus.

[X]

Originally Posted by jj

I think we ought to have a high-school class on swordmaking. From casting the blank to working it (with modern hammers, etc), to sharpening it.

What say?

You could choose, modern vanadium tool steel or do your own Damascus.

I'll take plain old carbon steel. Tool steel is too brittle.

PS: Damascus is the finished product. The raw form is Wootz steel.



Edit: NOVA recently aired a good program on making the Katana, covering the topic from the forging of steel to the polishing of the blade.
The show is called Secrets of the Samurai Sword, and although it leans towards over-hyping the Katana as the bestes, most coolest sword ever made, it covers the metallurgey quite well. Subjects touched upon include hardness/toughness, testing of such, crystallography (at different temperatures), impurities and imperfections, heat treating, and the effect of carbon.
http://www.pbs.org/wgbh/nova/samurai/. Hopefully the link works for you (it tdidn't for me).

[X]

double post

[jj]

Originally Posted by [X]

I'll take plain old carbon steel. Tool steel is too brittle.

I thought there was some pretty springy stuff out there. I could certainly be wrong.

Quote:

PS: Damascus is the finished product. The raw form is Wootz steel.

Of course, that's why I said "make your own Damascus". Fold, treat, fold, treat, fold, treat, use a modern triphammer, not a 3lb hammer, too.

[The Man]

Originally Posted by jj

I think we ought to have a high-school class on swordmaking. From casting the blank to working it (with modern hammers, etc), to sharpening it.

What say?

You could choose, modern vanadium tool steel or do your own Damascus.

Well it would certainly interest me, but the aspect of making specifically a weapon might not go over that well with the local board of education. Although it does present the practical application of most of the aspects of metallurgy and I can not think of a less “offensive” example that would do that.

[JoeEllison]

Originally Posted by jj

I thought there was some pretty springy stuff out there. I could certainly be wrong.

Yes, there is... I have a katana made from spring steel. A little silicon goes a long way.

[X]

Leaf spring knives are a very popular beginner project for smithing.
Blades made from steel cable are also popular, but more complicated due to the need to fuse the individual strands.


Ultimately, I'd say keep it simple. Do some basic theory (very brief, very simple) on the subjects I mentioned, and if the school has a metal shop, take advantage of it.
Some experiments are extremely easy to do, if the shop has some basic tools.


And I apologize to jj.
I misunderstood his comment about damascus.

[jj]

Originally Posted by The Man

Well it would certainly interest me, but the aspect of making specifically a weapon might not go over that well with the local board of education.

Ok, make sodcutter plows?

[jj]

Originally Posted by [X]

And I apologize to jj.
I misunderstood his comment about damascus.

Not an issue, I steel myself for these things, even with no WalMart in sight.

(p.s. 3 points to any non-metalurgy types for finding the second pun in that sentence)

[The Man]

Originally Posted by jj

Ok, make sodcutter plows?

Works for me, as long as the local board of education does not require them to beat our swords into plowshares and spears into pruning hooks.

[The Man]

Originally Posted by [X]

Leaf spring knives are a very popular beginner project for smithing.
Blades made from steel cable are also popular, but more complicated due to the need to fuse the individual strands.


Ultimately, I'd say keep it simple. Do some basic theory (very brief, very simple) on the subjects I mentioned, and if the school has a metal shop, take advantage of it.
Some experiments are extremely easy to do, if the shop has some basic tools.


And I apologize to jj.
I misunderstood his comment about damascus.

In my high school metal shop we actually did sand castings (I thing it was bronze, but it was a long time ago) much like in the olden days. Later as engineer I was able observe (and design components manufactured by) modern production casting (at least at that time). I think any high school metal shop should do both, give students hands on training with metal casting (which is simple technology) and expose them to the environment and technology (from investment casting to sintered metals, even drop forging and extrusion) of current metal production. I doubt that any company would deny access to a class tour, but would the powers that be defer their safety concerns for the benefit of the students? Metal, mold (or die), some heat (or not) and pressure, the basic principles are simple but the intricacies and resulting properties are varied. Swaging was one of the metal material production applications that I always found most interesting (combining pressure and the working flow of metal) and although a major process of one of the companies I worked for, I was not involved much in that production process and never had the opportunity to design tooling for.

“Say, any of you boys smithies? Or, if not smithies per se, were you otherwise trained in the metallurgic arts before straitened circumstances forced you into a life of aimless wanderin'?” Ulysses Everett McGill “O Brother, Where Art Thou”

[SirPhilip]

Originally Posted by [X]

Start with the basics: material properties.

Properties of the behavior of nonliving matter. Let's humanize it.

Stress



Strain



Strength



Stiffness



Hardness



Elasticity



Tension



Compression



Hooke's Law



Deformation

Quote:

Some apply to stress analysis as well, but all are fundamental to material science. Then, once the basics are understood, you can progress to things like strain hardening, ductility, brittleness, temperature effects, and the like.

You keep telling yourself that.

[Terry]

martensite, maybe?

[Doubt]

Well, I am a controls guy who works in the heat-treat industry and used to work in a steel mill.

The ASM, American Society of Metals, used to have a self taught course called "Metallurgy for the non-metallurgist." It was mostly about steel, however.

Not sure how you would do a high school course with labs. Lots of ways to get hurt there, as JJ pointed out.

If you want to get kids interested in the subject, start with the salaries of metallurgists.

As for the tools steel comment, try austempered ductile iron. Less brittle. (Disclaimer, the guy who founded our company also owns a very useful patent on a process for austempering.)

[jj]

Originally Posted by Terry

martensite, maybe?

Terry gets the 3 points.

[GreyICE]

Isn't Mat Sci pretty much the most boring thing ever though?

If we want kids interested in Engineering, why not Thermodynamics? It's absolutely the most basic principles of Engineering (all engineers, like it or not (even you, Civil) deal with energy) and is quite interesting to boot.

Mat Sci is just boring combined with moments of intense frustration.

The only fun part would be doing the steel cooling experiment with Mo's hardness testers to show quenched steel is harder than steel that is allowed to cool slowly, and also showing the rearranging of the molecular structures in steel based on temperature (something I found fascinating).

[Sunstealer]

Originally Posted by GreyICE

Isn't Mat Sci pretty much the most boring thing ever though?

If we want kids interested in Engineering, why not Thermodynamics? It's absolutely the most basic principles of Engineering (all engineers, like it or not (even you, Civil) deal with energy) and is quite interesting to boot.

Mat Sci is just boring combined with moments of intense frustration.

The only fun part would be doing the steel cooling experiment with Mo's hardness testers to show quenched steel is harder than steel that is allowed to cool slowly, and also showing the rearranging of the molecular structures in steel based on temperature (something I found fascinating).

Absolute basic does not mean most interesting.

This (my bolding) made me laugh. I can't think of anything worse than being subjected to thermodynamics at an early age, it was bad enough during my degree. My experience of getting into the materials world (and therefore exposure to other subjects) was not one of thermodynamics even though I was studying some of it at A-level (it was of mountain bikes, their manufacture, lightness etc). There is nothing fun about differing cooling rates and their affects on the properties of steels (even with samples and microstructures). Much better to ask far more real world questions and their applications that might have a bearing.

Metallurgy or Materials Engineering is a profoundly physical subject that is tangible to everyone who has ever held a piece of metal or any other smelted/extracted and/or manufactured good(s), however, when studied it's far deeper and it's the degree of how deep the rabit hole goes for pupils of the age the OP is interested in. There are certainly lots of teaching aids available via a great many organisations. Materials Engineering extends so far into our modern world it's unbelievable when you look - everything from a silicon chip to a frying pan (coated with teflon). It has so many specialist subsets that an all encompassing subject is hard to teach - doubly so at the level the OP is asking for and this is why it's so difficult to give an idea at a pre 18 age. You can teach a large part of the world (and many other much needed concepts) to pupils simply by expanding their knowledge of basic science and how they see materials (metals, polymers, ceramics).

Thermodynamics is important, vastly important, and whilst it does allow for expansion into a good number of areas it becomes complex and detached from experience quite quickly (imho).

I wouldn't want to ever teach (high school) students about relative hardness with cooling rates without a prop or physical concept that they could see themselves and understand the need for an application in a wider world.

Materials science isn't for everyone and I fondly remember my very bright (much brighter than me) friend trying to understand some of the basics (as he was required to appreciate) in his Mechanical Engineering course, as I laughed. I tried as much as I could to explain and he did indeed grasp alot of the concepts, but never had a solid grasp of them (but then again he wasn't required to - the mat science was a small part of his course). And I guess this is where alot of people find it obscure/not interesting/important. I'm not surprised. Similarly when I quizzed him about what he was doing and why, I could also grasp the concepts, but not the details and he would laugh at me.

Science is not an all encompassing genre, there are many nuances and just because one understands one nuance does not automatically mean one understands another not matter if they are closely related. The thing about science is that it is there. Regardless of whether one grasps or enjoys one or multiple, related or non-related subjects.

However, one thing is sure; the material can drive the science in what ever way anyone likes. I think it's important for children to grasp the basics from a material view involving experimentation and above all fun, it gives them a practical feel and does not mean in anyway they'll all turn into metallurgists.

( I'd love to find out what everyone thinks is an archetypal metallurgist - I'm sure I've met a few of them!).

[GreyICE]

Originally Posted by Sunstealer

Absolute basic does not mean most interesting.

This (my bolding) made me laugh. I can't think of anything worse than being subjected to thermodynamics at an early age, it was bad enough during my degree. My experience of getting into the materials world (and therefore exposure to other subjects) was not one of thermodynamics even though I was studying some of it at A-level (it was of mountain bikes, their manufacture, lightness etc). There is nothing fun about differing cooling rates and their affects on the properties of steels (even with samples and microstructures). Much better to ask far more real world questions and their applications that might have a bearing.

I don't have any idea how this DOESN'T have a real world bearing. The fact that different molecular structures can form out of the same material is fascinating. As for Thermo, I just don't understand how someone can't like it.

For mountain bikes, I'll let you in on a little secret. You can take all that Mat Sci and toss it out the window. They're going to use the cheap abundant metals anyway, and that means aluminum alloys, steel alloys, or carbon fiber (not a metal, but you know what I mean). Titanium makes an awesome bike frame, but unless it's the olympics, not gonna happen.

Then you can run your basic calculations, and then throw them out the window and give everything a Factor of Safety of at least 2.

Quote:

Metallurgy or Materials Engineering is a profoundly physical subject that is tangible to everyone who has ever held a piece of metal or any other smelted/extracted and/or manufactured good(s), however, when studied it's far deeper and it's the degree of how deep the rabit hole goes for pupils of the age the OP is interested in. There are certainly lots of teaching aids available via a great many organisations. Materials Engineering extends so far into our modern world it's unbelievable when you look - everything from a silicon chip to a frying pan (coated with teflon). It has so many specialist subsets that an all encompassing subject is hard to teach - doubly so at the level the OP is asking for and this is why it's so difficult to give an idea at a pre 18 age. You can teach a large part of the world (and many other much needed concepts) to pupils simply by expanding their knowledge of basic science and how they see materials (metals, polymers, ceramics).

It's inconceivably boring. It's literally the most boring thing I ever experienced in school. Sure, it sounds cool, until you realize that every practical thing you do with it is intensely boring.

Quote:

Thermodynamics is important, vastly important, and whilst it does allow for expansion into a good number of areas it becomes complex and detached from experience quite quickly (imho).

Not really. Energy balances are an absolute function of anything that:

Generates heat
Involves movement
Uses energy

That's a HUGE range of practical areas.

Quote:

I wouldn't want to ever teach (high school) students about relative hardness with cooling rates without a prop or physical concept that they could see themselves and understand the need for an application in a wider world.

Yeah, we did it with an autoclave, steel samples, a Mo's Hardness tester, and 800 degree samples.

Minus handling 800 degree samples (the teacher could do it) it's reasonably practical.

Quote:

Materials science isn't for everyone and I fondly remember my very bright (much brighter than me) friend trying to understand some of the basics (as he was required to appreciate) in his Mechanical Engineering course, as I laughed. I tried as much as I could to explain and he did indeed grasp alot of the concepts, but never had a solid grasp of them (but then again he wasn't required to - the mat science was a small part of his course). And I guess this is where alot of people find it obscure/not interesting/important. I'm not surprised. Similarly when I quizzed him about what he was doing and why, I could also grasp the concepts, but not the details and he would laugh at me.

Science is not an all encompassing genre, there are many nuances and just because one understands one nuance does not automatically mean one understands another not matter if they are closely related. The thing about science is that it is there. Regardless of whether one grasps or enjoys one or multiple, related or non-related subjects.

However, one thing is sure; the material can drive the science in what ever way anyone likes. I think it's important for children to grasp the basics from a material view involving experimentation and above all fun, it gives them a practical feel and does not mean in anyway they'll all turn into metallurgists.

( I'd love to find out what everyone thinks is an archetypal metallurgist - I'm sure I've met a few of them!).

He works in a boring field.

Seriously, I'm like your ME friend (I'm an ME, fancy that). You can't send me to sleep faster than exposing me to Mat Sci.

[Sunstealer]

Originally Posted by GreyICE

I don't have any idea how this DOESN'T have a real world bearing. The fact that different molecular structures can form out of the same material is fascinating.

It is and it's not intuitive either and also has real world applications.

Originally Posted by GreyICE

For mountain bikes, I'll let you in on a little secret. You can take all that Mat Sci and toss it out the window. They're going to use the cheap abundant metals anyway, and that means aluminum alloys, steel alloys, or carbon fiber (not a metal, but you know what I mean). Titanium makes an awesome bike frame, but unless it's the olympics, not gonna happen.

MS is not just about the metal or the alloy. It's the whole process from getting material from the ground, extracting the metal, alloying, processing and forming and heat treatment (if needed). Welding and joining (which I find a boring topic) is a whole science in itself. I remember when a cromoly welded steel (rather than brazed) was an expensive item as opposed to the hi-tensile crap that was heavy. The development of steel tubing for bicycle frames from rubbish to aermet 100 is quite a feat. I remember when aluminium frames were rare as hens teeth and very, very expensive, now they are 10 a penny and the cheapest bikes now use that material. There was extensive development in the manufacture and design of the tubing, but more importantly the preparation and joining (Cannondale's website is a good one). Titanium frames are expensive, but they have been around a long time (see Litespeed) and are quite readily available. Infact my dad has a cheap Raleigh Dynatec MTB that uses Ti for the front triangle (bonded into Al lugs) with a bolt on steel rear triangle (Gary Fisher did something similar first with aluminium front triangle). Carbon fibre is about as expensive as Ti but gives a completely different ride and can be fashioned into different shapes that normal tubing can't (See Trimble, my brother has had one since early 90's). Bike frames have been made from cast magnesium (Kirk Precision) and even Beryllium (American Bicycle Manufacturing) and cost $26,000! Yes I could bore for GB on mountain bikes if it was an Olympic sport.

Originally Posted by GreyICE

Then you can run your basic calculations, and then throw them out the window and give everything a Factor of Safety of at least 2.
It's inconceivably boring. It's literally the most boring thing I ever experienced in school. Sure, it sounds cool, until you realize that every practical thing you do with it is intensely boring.

So the manufacture of everything in the post industrialised world is boring eh? From railway boilers to silicon chips. MS isn't just about metals there's ceramics, polymers, metal-matrix composites, ceramic-matrix composites, glasses, etc - with a huge range of applications. Without metallurgy and the mass production of quality steel we would certainly not see the world as we know it for metallurgy was a huge part of the industrial revolution which has driven the western world for the past 150 years.

The world would be a pretty boring place if everyone liked the same subjects. Obviously we differ and that's fine. Hell I've made a career out of it!

[jj]

Originally Posted by Sunstealer

and even Beryllium (American Bicycle Manufacturing) and cost $26,000!

Um, when you fall on it, and scrape some metal off the side, do you have to call the EPA pronto?

YIKES!

[196]

I agree that metallurgy is an interesting and useful topic. The content of classes (called "courses" in Canada) is set by provincial governments. The Ontario curriculum for science doesn't include metallurgy in any topic in any of the strands (units):
Ontario curriculum for Grades 11 and 12 science
Ontario curriculum for Grades 9 and 10 science

A teacher could still work it in, but it couldn't be an entire unit. FWIW, the science teacher at my school does a bit of metallurgy with her classes.

What if, instead of a class, you could design a single lesson that would take one or two periods (say 150 minutes maximum). What would you want students to experience? Next year I'm scheduled to teach math and possibly one grade 9 science in second semester. If I get that science class, I'll come back and get some ideas to include a metallurgy lesson in the "exploring matter" topic of the chemistry strand (Ontario curriculum for Grades 9 and 10 science). As an example, we could explore the effects of heat treating (heat & quench one day, bend or break the next day).

[Sunstealer]

Originally Posted by jj

Um, when you fall on it, and scrape some metal off the side, do you have to call the EPA pronto?

YIKES!

Be is only hazardous in dust form, it's quite safe to handle, I've done it a few times. What is crazy is committees getting overzealous and banning it in alloys (eg: Al castings where it acts as a grain refiner consequently improves fatigue properties and BeO layer to prevent oxidation in the melt) even though it's beneficial and the introduction of Be is done prior to casting usually as BeCu and the machining of said castings are all 5 axis CNC enclosed machines (even though open would be fine) . Adds cost because AlBe aerospace alloys are standard and requires addition materials testing to gather data on the material behaviour for stress/design engineers etc.

Originally Posted by 196

What if, instead of a class, you could design a single lesson that would take one or two periods (say 150 minutes maximum). What would you want students to experience? Next year I'm scheduled to teach math and possibly one grade 9 science in second semester. If I get that science class, I'll come back and get some ideas to include a metallurgy lesson in the "exploring matter" topic of the chemistry strand (Ontario curriculum for Grades 9 and 10 science). As an example, we could explore the effects of heat treating (heat & quench one day, bend or break the next day).

Effect of heat treatment (including quench and temper) of steels is a good one. It shows change of properties very well and you can tie this in with most of the basics whilst giving the children something visual to focus on. It would be cheap too as no machinery is needed other than a forge/furnace and a bucket plus water/oil (quenching bath). 4 pieces is all you need - one control, one heated to austenite temp and air cooled, one quenched in water/oil, one quenched and tempered. Then the you can show them that the properties are reversible by going back to the austenite temperature or higher and air or furnace cool.

Hint: Austenite is non-magnetic so you don't need a thermocouple just place the metal next to a magnet. If it sticks it's not in the austenitic region, if it doesn't then you have reached the austenitic region on the phase diagram - approx 730°C.

[neutrino_cannon]

Originally Posted by GreyICE

I just feel I have to comment on this.

Springs are used because they are predictable, versatile, and reliable. If they weren't, we'd use something else (for instance piston-cylinders full of air replicate many/most of the properties of springs very easily).

It is not fortunate that springs have those properties. The inventions use springs because they have those properties. It's the good ol' puddle marveling at the hole that exactly fits it.

Compared to the reliability of pneumatic buffers (which are used in some applications), springs are far cheaper and less sensitive to environmental conditions, and scale better.

Indeed, compared to most other human inventions, metal springs are unusually cheap, environmentally insensitive, and scalable. Surely that is worthy of remark?

Quote:

What if, instead of a class, you could design a single lesson that would take one or two periods (say 150 minutes maximum). What would you want students to experience? Next year I'm scheduled to teach math and possibly one grade 9 science in second semester. If I get that science class, I'll come back and get some ideas to include a metallurgy lesson in the "exploring matter" topic of the chemistry strand (Ontario curriculum for Grades 9 and 10 science). As an example, we could explore the effects of heat treating (heat & quench one day, bend or break the next day).

I like this idea. For a grade 9 introduction this sounds just short and informative enough to keep attention and possibly spark more interest.