Scientists develop 'unbreakable' glass almost as tough as steel(ajw.asahi.com)
ajw.asahi.com
Scientists develop 'unbreakable' glass almost as tough as steel
http://ajw.asahi.com/article/sci_tech/technology/AJ201510290034
74 comments
Indeed. A method of making glass via a containerless processing system that I am aware of, is aerodynamic levitation, wherein a ball of starting material is suspended in a stream of gas, such as Ar, and heated by lasers. This method is used in systems that tend to crystallise rapidly rather than quench to a nice glass, since the thermal mass of the sample is very small and you can take all the heat away instantly by tunring off the laser. Samples prepared by such a method are typically 100s to 1000s of microns in diameter. I would be very interested to hear how they would scale this method to industrial production, if aerodynamic levitation is how they made their glass.
Sorry, But That New Glass From Japanese Researchers Isn't Unbreakable
http://www.forbes.com/sites/carmendrahl/2015/11/03/sorry-but...
http://www.forbes.com/sites/carmendrahl/2015/11/03/sorry-but...
A few questions on applicability
1. Would this be good for a car? Is having a mostly unbreakable windshield a good thing?
2. How would it handle for cookware? Will it last even if an ignorant person left it in the oven for hours on end?
3. What about uses on phones? Can I have both a scratch resistant touch screen that also doesn't fracture if I drop it 3ft onto asphalt?
4. What does it do in reaction to sunlight? How insulative is it if used in buildings and homes?
5. Is it non reactive for biomedical uses? Does it deteriorate over time? How stable is it?
1. Would this be good for a car? Is having a mostly unbreakable windshield a good thing?
2. How would it handle for cookware? Will it last even if an ignorant person left it in the oven for hours on end?
3. What about uses on phones? Can I have both a scratch resistant touch screen that also doesn't fracture if I drop it 3ft onto asphalt?
4. What does it do in reaction to sunlight? How insulative is it if used in buildings and homes?
5. Is it non reactive for biomedical uses? Does it deteriorate over time? How stable is it?
>2. How would it handle for cookware? Will it last even if an ignorant person left it in the oven for hours on end?
Pyrex has been around since the 1910s and doing this just fine ever since.
Pyrex has been around since the 1910s and doing this just fine ever since.
Well, Corning sold the brand name Pyrex around 2000. A post-2000 Pyrex item may not have the same composition as the Corning product you're more familiar with.
The composition of the Pyrex glass sold in North America did change from borosilicate glass to soda-lime glass when the brand changed hands, yes. But the important thing about "glass not breaking at high temperatures" has much more to do with the annealing process than it does the type of glass.
Pyrex will shatter if you take it out of a blistering hot oven and pour cold water on it (e.g. to let stuck on food soak).
Yah...I just learned this the hard way. I took it out of the oven and put in on the cold granite countertop.
I never said that Pyrex is unbreakable. But it certainly wont break just because "an ignorant person left it in the oven for hours on end".
Almost every material known to man will break/crack/shatter/do-something if you rapidly cool it from an elevated temperature.
Almost every material known to man will break/crack/shatter/do-something if you rapidly cool it from an elevated temperature.
Yeah, taking a piping hot casserole dish out of the oven and placing it on a damp rag on my counter showed me this feature. Pretty terrifying at the time.
Finally, we can keep humpback whales in our starships!
Serious question, couldn't they have just used steel walls and grabbed the whales no problem?
I see no reason that they needed to be able to see through the walls and look at the Wales inside.
I see no reason that they needed to be able to see through the walls and look at the Wales inside.
This could revolutionize knife making. A steel knife is always like a saw on micro level. A glass (like obsidian) could get properly sharp. A glass with the properties of steel is a dream come true.
I think the "containerless processing technique" is an acoustic levitator. My friend was on the team building one for a Japanese investor who wanted to make a wine glass that didn't break when you knocked it over on your fancy granite worktop.
See one working https://youtu.be/0K8zs-KSitc
See one working https://youtu.be/0K8zs-KSitc
Make bottles out of this, sell them, return a deposit to get them back. Wash them. Reuse.
Here's a link to the paper itself if you have access: http://www.nature.com/articles/srep15233
Please start with the iphone. Damn thing shatters if I look at it funny.
Man, I've never had a problem with a broken iPhone screen. I worked for months on a pretty large construction site breaking up concrete while dropping my phone fairly regularly and it's still aces.
Obviously a stronger screen would be great, but a case does wonders if you want a functioning phone for now.
Obviously a stronger screen would be great, but a case does wonders if you want a functioning phone for now.
yup, hindsight...
I never had a problem with a phone screen breaking until the 6 plus. My OnePlus is bulletproof.
I never had a problem with a phone screen breaking until the 6 plus. My OnePlus is bulletproof.
I bet the British government will try to ban this too.
Put it on an iPhone and it will shatter. Guaranteed.
Sounds like a hybrid between glass and "transparent aluminium".
So... Gorilla glass?
edit: yeah...
From: https://en.wikipedia.org/wiki/Gorilla_Glass
Gorilla Glass is a brand of specialized toughened glass developed and manufactured by Corning, now in its fourth generation,[1] designed to be thin, light and damage-resistant. This type of glass is not unique to Corning; similar glasses include Asahi Glass Co. Dragontrail and Schott AG Xensation.[2][3]
The alkali-aluminosilicate sheet glass [snip]
(The link is to asahi.com)
edit: yeah...
From: https://en.wikipedia.org/wiki/Gorilla_Glass
Gorilla Glass is a brand of specialized toughened glass developed and manufactured by Corning, now in its fourth generation,[1] designed to be thin, light and damage-resistant. This type of glass is not unique to Corning; similar glasses include Asahi Glass Co. Dragontrail and Schott AG Xensation.[2][3]
The alkali-aluminosilicate sheet glass [snip]
(The link is to asahi.com)
Gorilla glass uses a post-solidification hardening step.
The glass described in the article uses a higher aluminum content than any other mass-produced glass, to the point where any contact with a solid surface would produce alumina crystals rather than incorporate the aluminum into the glass structure.
So they levitated a glass bead with a continuous stream of air until it solidified. The bead is very strong, but they have no idea how to work the resulting glass into fibers or sheets.
The glass described in the article uses a higher aluminum content than any other mass-produced glass, to the point where any contact with a solid surface would produce alumina crystals rather than incorporate the aluminum into the glass structure.
So they levitated a glass bead with a continuous stream of air until it solidified. The bead is very strong, but they have no idea how to work the resulting glass into fibers or sheets.
>> (The link is to asahi.com)
Asahi Glass Co. is a separate company to Asahi Shimbun, the news organisation. AGC has a historical connection to the Mitsubishi group through the founder's family, but really is a wholly independent group of companies.
Asahi Glass Co. is a separate company to Asahi Shimbun, the news organisation. AGC has a historical connection to the Mitsubishi group through the founder's family, but really is a wholly independent group of companies.
Sapphire crystal [1] is something like transparent aluminum rust. Alumina [2] is too, I think. They might be the same thing, I'm not a chemist.
[1] https://en.wikipedia.org/wiki/Sapphire [2] https://en.wikipedia.org/wiki/Aluminium_oxide
[1] https://en.wikipedia.org/wiki/Sapphire [2] https://en.wikipedia.org/wiki/Aluminium_oxide
Alumina is Al2O3 generally, and usually it is polycrystalline. Sapphire is specifically Al2O3 in a certain (very hard) crystal structure.
Sapphire and ruby are both aluminum oxide - i.e. 'alumina' - just with different kinds and amounts of impurities.
Yes, it is technically the stuff you get when you throw aluminum powder over a fire and it lights up and burns brightly. But the crystals you obtain that way are very tiny.
Yes, it is technically the stuff you get when you throw aluminum powder over a fire and it lights up and burns brightly. But the crystals you obtain that way are very tiny.
While it's not quite transparent aluminum, transparent aluminum oxide ceramics like ALON are used for ballistic armor on ships, helicopters, and other military vehicles.
https://www.youtube.com/watch?v=RnUszxx2pYc
https://www.youtube.com/watch?v=RnUszxx2pYc
Aye, that's the ticket, laddie!
Upvoted this to counteract the idiots.
For those downvoting this, please go watch Star Trek IV: The Voyage Home
What if that's the reason they are downvoting it? The anti fun knob is probably unnecessarily cranked to 11 here, but movie references aren't really that funny.
> cranked to 11 here... movie references
Intentional reference to https://en.wikipedia.org/wiki/Up_to_eleven#Original_scene_fr... ?
Intentional reference to https://en.wikipedia.org/wiki/Up_to_eleven#Original_scene_fr... ?
[deleted]
Yes, please. I upvoted it. It doesn't deserve any downvotes.
Fiction becoming reality. I thought "transparent aluminum" was just completely made-up nonsense when I saw the movie. Whodda thunk!
Fiction becoming reality. I thought "transparent aluminum" was just completely made-up nonsense when I saw the movie. Whodda thunk!
Wait. A big elasticity coefficient is not the same as 'unbreakable'.
Being a mixture of silicates and alumina, I'll be very surprised if this is not fragile. There's nothing about it on the article.
Being a mixture of silicates and alumina, I'll be very surprised if this is not fragile. There's nothing about it on the article.
Glass itself isn't always "fragile" https://en.wikipedia.org/wiki/Prince_Rupert%27s_Drop so perhaps we'll be pleasantly surprised
Oh man, I love Prince Rupert's Drop. As usual, Smarter Every Day has a great video on them: https://www.youtube.com/watch?v=xe-f4gokRBs
This is cool regardless. But I am interested in cost and weight.
If it is too costly we might only see it used in niche applications (e.g. aircraft windows?). But even then if it weighs more than regular glass it may not even be utilised there.
I'd like to see it used on vehicle front windshields, cracks are a constant pain in the butt, and they can leave the rear window and side windows as regular glass for emergency escape (typically only the front one receives most of the debris). But it really comes back to both weight and cost again.
If it is too costly we might only see it used in niche applications (e.g. aircraft windows?). But even then if it weighs more than regular glass it may not even be utilised there.
I'd like to see it used on vehicle front windshields, cracks are a constant pain in the butt, and they can leave the rear window and side windows as regular glass for emergency escape (typically only the front one receives most of the debris). But it really comes back to both weight and cost again.
Your windshield is safety glass, so consideration must be given for the need to dissipate energy when a human head collides with it.
https://en.wikipedia.org/wiki/Windshield#Safety
Trivia: A famous lawsuit about the safety of windshield glass was the _Pane_ vs. Ford case in 1917
https://en.wikipedia.org/wiki/Windshield#Safety
Trivia: A famous lawsuit about the safety of windshield glass was the _Pane_ vs. Ford case in 1917
I don't think that safely fracturing when struck by a human is the safety function referred to in the linked article - once a person hits the windshield, the primary safety mechanisms (seatbelts, airbags, and structural integrity of the car) have already failed, so whatever happens at the windshield will make little difference.
What the article says is that the safety role of a windshield (besides not breaking into dangerous shards of glass) is in being strong enough to maintain the structural integrity of the passenger compartment:
Modern, glued-in windshields contribute to the vehicle's rigidity, but the main force for innovation has historically been the need to prevent injury from sharp glass fragments. Almost all nations now require windshields to stay in one piece even if broken, except if pierced by a strong force. Properly installed automobile windshields are also essential to safety; along with the roof of the car, they provide protection to the vehicle's occupants in the case of a roll-over accident.
Today’s windshields are a safety device just like seat belts and airbags. The installation of the auto glass is done with an automotive grade urethane designed specifically for automobiles. The adhesive creates a molecular bond between the glass and the vehicle. If the adhesive bond fails at any point on the glass it can reduce the effectiveness of the air bag and substantially compromise the structural integrity of the roof.
What the article says is that the safety role of a windshield (besides not breaking into dangerous shards of glass) is in being strong enough to maintain the structural integrity of the passenger compartment:
Modern, glued-in windshields contribute to the vehicle's rigidity, but the main force for innovation has historically been the need to prevent injury from sharp glass fragments. Almost all nations now require windshields to stay in one piece even if broken, except if pierced by a strong force. Properly installed automobile windshields are also essential to safety; along with the roof of the car, they provide protection to the vehicle's occupants in the case of a roll-over accident.
Today’s windshields are a safety device just like seat belts and airbags. The installation of the auto glass is done with an automotive grade urethane designed specifically for automobiles. The adhesive creates a molecular bond between the glass and the vehicle. If the adhesive bond fails at any point on the glass it can reduce the effectiveness of the air bag and substantially compromise the structural integrity of the roof.
> once a person hits the windshield, the primary safety mechanisms (seatbelts, airbags, and structural integrity of the car) have already failed, so whatever happens at the windshield will make little difference.
There used to be an issue where people's head would go through a window but the glass wouldn't entirely shatter, so the rest of the body wouldn't go through. A deadly broken window collar
Source: took the same tech class 2 years in a row, and watched some documentary on car safety _4 times_ each year. Yay for American middle school
There used to be an issue where people's head would go through a window but the glass wouldn't entirely shatter, so the rest of the body wouldn't go through. A deadly broken window collar
Source: took the same tech class 2 years in a row, and watched some documentary on car safety _4 times_ each year. Yay for American middle school
Windshields are laminated safety glass, which it sounds like you might be confusing with tempered safety glass. There's a huge difference in how those break.
Laminated glass remains in one solid mass held together by the plastic sheet in the middle, while tempered glass explodes into tiny pieces that are sharp but not overly harmful. Ordinary annealed glass breaks into long, dagger-like pieces that are dangerously sharp, which is why it's tempered or laminated into safety glass.
So the windshield is meant not to break apart, because it's laminated rather than tempered. The polymer lining between the lites of glass prevents it from scattering and causes it to be quite impact resistant. [1] Conversely, you'd really hate to have tempered glass as your windshield, if it broke the entire thing would just pop into tiny pieces that would get into your eyes. If a rock hit hard enough to break a hypothetical tempered windshield, the parts that didn't pop would be filled with cracks and impossible to see through due to being white from being filled with tiny cracks, though you could just bat them out of the way as any parts were partially intact would simply crumble when moved.
The side windows are tempered, incidentally. If you've ever broken a side window, you know what I mean about the whole thing just exploding. [2] If you manage to pop it, the entire window will just fall apart easily, which might be good if you had to leave from the window of a car. It can cause small cuts and scratches and such, but it's not terribly dangerous unless it gets in your eyes, even if, say, a sheet of 3mm, 33 1/4 x 73 1/4 inch glass breaks while you're holding it. [3] It's no fun, but when you compare it to the fact that annealed glass accidents have been fatal, it's not so bad. [4] Yes, I used to work for a glass factory, so when I say that I've seen hundreds of tons of broken glass, the word 'tons' should be understood in the literal, 2,000 lbs sense of the word.
[1] Source: Determined empirically by beating on damaged pieces of it with a shovel, when said pieces wouldn't fit into the dumpster. Or you can read this, whatever: http://sem-proceedings.com/10f/sem.org-IMPLAST-2010-SEM-Fall...
[2] See also: https://www.youtube.com/watch?v=xPwaq_6aXbo This normally happens only if hit from the corner or an edge, but it can happen just randomly. We usually saw this in winter, but only a few times a year, meaning there was at most about a 1 in 10,000 chance of spontaneous breakage in my experience and probably significantly less based on the average daily volume numbers I remember. When there's something containing the edge of tempered, it sometimes just takes on a white, broken look due to all the cracks, but crumbles to the touch. It tends to just disintegrate like in the video most of the time, though.
[3] Source: Direct, personal experience on multiple occasions for that very size and many others. This is an every-day kind of thing and causes no injury to someone with proper safety gear.
[4] Source: I'm directly aware of at least one such accident where someone was found dead after having their neck cut when attempting to dispose of a cracked sheet. I also provided first aid to someone who could've lost a hand to injury.
Laminated glass remains in one solid mass held together by the plastic sheet in the middle, while tempered glass explodes into tiny pieces that are sharp but not overly harmful. Ordinary annealed glass breaks into long, dagger-like pieces that are dangerously sharp, which is why it's tempered or laminated into safety glass.
So the windshield is meant not to break apart, because it's laminated rather than tempered. The polymer lining between the lites of glass prevents it from scattering and causes it to be quite impact resistant. [1] Conversely, you'd really hate to have tempered glass as your windshield, if it broke the entire thing would just pop into tiny pieces that would get into your eyes. If a rock hit hard enough to break a hypothetical tempered windshield, the parts that didn't pop would be filled with cracks and impossible to see through due to being white from being filled with tiny cracks, though you could just bat them out of the way as any parts were partially intact would simply crumble when moved.
The side windows are tempered, incidentally. If you've ever broken a side window, you know what I mean about the whole thing just exploding. [2] If you manage to pop it, the entire window will just fall apart easily, which might be good if you had to leave from the window of a car. It can cause small cuts and scratches and such, but it's not terribly dangerous unless it gets in your eyes, even if, say, a sheet of 3mm, 33 1/4 x 73 1/4 inch glass breaks while you're holding it. [3] It's no fun, but when you compare it to the fact that annealed glass accidents have been fatal, it's not so bad. [4] Yes, I used to work for a glass factory, so when I say that I've seen hundreds of tons of broken glass, the word 'tons' should be understood in the literal, 2,000 lbs sense of the word.
[1] Source: Determined empirically by beating on damaged pieces of it with a shovel, when said pieces wouldn't fit into the dumpster. Or you can read this, whatever: http://sem-proceedings.com/10f/sem.org-IMPLAST-2010-SEM-Fall...
[2] See also: https://www.youtube.com/watch?v=xPwaq_6aXbo This normally happens only if hit from the corner or an edge, but it can happen just randomly. We usually saw this in winter, but only a few times a year, meaning there was at most about a 1 in 10,000 chance of spontaneous breakage in my experience and probably significantly less based on the average daily volume numbers I remember. When there's something containing the edge of tempered, it sometimes just takes on a white, broken look due to all the cracks, but crumbles to the touch. It tends to just disintegrate like in the video most of the time, though.
[3] Source: Direct, personal experience on multiple occasions for that very size and many others. This is an every-day kind of thing and causes no injury to someone with proper safety gear.
[4] Source: I'm directly aware of at least one such accident where someone was found dead after having their neck cut when attempting to dispose of a cracked sheet. I also provided first aid to someone who could've lost a hand to injury.
I thought windshields are tempered and laminated. Not that it significantly changes what you said. Just explains why occasional shards flying away from windshields are not that sharp.
I have never heard of a glass that's tempered & laminated. I'm not sure you could temper a glass flat enough to laminate it, either--it moves on rollers during the entire tempering process to keep it (mostly) flat, but it's nowhere near as flat as it is coming from the float plant and distortion is measured as part of the QC process.
You also can't temper any laminate that I know of--the liner would simply melt and cause a mess in the furnace. Our tempering furnace operated in the 700-800F range.
They might seam the edges of the laminate, though, like you do with annealed glass before tempering. I didn't work with windshields, only window glass, including some 6mm clear tempered that went to Google.
You also can't temper any laminate that I know of--the liner would simply melt and cause a mess in the furnace. Our tempering furnace operated in the 700-800F range.
They might seam the edges of the laminate, though, like you do with annealed glass before tempering. I didn't work with windshields, only window glass, including some 6mm clear tempered that went to Google.
Tempered laminated exists. But I can't find anything about it being used in car windshields. My bad, sorry.
The way I would do it would be chemical tempering before laminating. Then you probably have lot less warping.
The way I would do it would be chemical tempering before laminating. Then you probably have lot less warping.
Yes, the break pattern of a windshield is consistent with annealed glass. If it were tempered, the entire window could become an opaque white whenever it was damaged by a rock and that just wouldn't be safe. Not that the 'spiderweb' pattern is easy to see through, but it's better than being fully opaque.
I'm not familiar with any tempered laminates as we never made such, but a chemical process sounds more reasonable than trying to get laminated glass through a tempering furnace or laminate two tempered lites.
I'm not familiar with any tempered laminates as we never made such, but a chemical process sounds more reasonable than trying to get laminated glass through a tempering furnace or laminate two tempered lites.
Yes, but your analysis discounts vehicles striking pedestrians and cyclists.
Well, no my analysis points out that the main safety purpose of windshield glass is to protect the structural integrity of the occupant cage -- it can't both protect against outside impact and penetration while also being a soft cushion for peoples heads to impact.
A window could give way in either direction without being penetrated, for example by stretching out and permanently deforming. Risk for people inside is that it would give too much way, so that that pole hits your head.
If it's flexible it's not going to support the roof in a rollover -- the windshield is a structural part of the occupant cage.
"Permanently deforming" and "flexible" are different things. The crumple zone of a car isn't flexible, but does deform.
But yes, this probably would either limit what you can do there or necessitate design changes (just like it would glass with some new properties)
But yes, this probably would either limit what you can do there or necessitate design changes (just like it would glass with some new properties)
Glass has density of ~2,5 kg/liter. It's made of silica, that has density of ~2,6. This has about 50% of Alumina in it with typical density of ~4.
So it's likely it would be around 3,3. More than aluminum, less than titanium.
But it's supposedly about ~20 times more rigid than regular glass. For rigidity limited structure, you could make it so much thinner that you get significant weight savings. This could be important for glass fiber structures. Fiber vs. fiber, glass has been able to compete in strength with carbon fiber, but lack of rigidity is the downside. Increase of stiffness might allow for usage of stiffer "matrix" (glue that holds the fibers together). That should increase overall strength. This limitation exists because if matrix is stiffer than the fibers, the structure will rip itself apart under load.
For strength or hardness limited designs, impossible to say. The article says nothing about it. Alumina is one of the hardest substances around, but I would not make any assumptions based on that. Typically it's more about structure than the molecules involved.
For creep and fatigue resistant designs, bulk glasses are pretty useless because of their amorphous structure. Fibers can be used in fatigue situation though. Again the increase in stiffness and the possible increase of matrix stiffness could improve the situation. But the real thing here is how well the matrix can bind to the fibers. That again is impossible to tell.
Windshields? It's big trade off really. Soft amorphic materials scratch easily. (By definition "hardness" is resistance to identation. Just add movement and you have scratching.) Typically "hard" amorphic materials suffer from cracking. This is because hardness usually comes with decreased ductility. But fracture toughness is function of stiffness and ductility. So this material could(?!?) improve hardness while being about as easy cracking as old windshiels. This would be good idea as windshield is mostly mode of fracture limited design. (It matters more how your windshield breaks, than how much energy it takes to break it.)
So it's likely it would be around 3,3. More than aluminum, less than titanium.
But it's supposedly about ~20 times more rigid than regular glass. For rigidity limited structure, you could make it so much thinner that you get significant weight savings. This could be important for glass fiber structures. Fiber vs. fiber, glass has been able to compete in strength with carbon fiber, but lack of rigidity is the downside. Increase of stiffness might allow for usage of stiffer "matrix" (glue that holds the fibers together). That should increase overall strength. This limitation exists because if matrix is stiffer than the fibers, the structure will rip itself apart under load.
For strength or hardness limited designs, impossible to say. The article says nothing about it. Alumina is one of the hardest substances around, but I would not make any assumptions based on that. Typically it's more about structure than the molecules involved.
For creep and fatigue resistant designs, bulk glasses are pretty useless because of their amorphous structure. Fibers can be used in fatigue situation though. Again the increase in stiffness and the possible increase of matrix stiffness could improve the situation. But the real thing here is how well the matrix can bind to the fibers. That again is impossible to tell.
Windshields? It's big trade off really. Soft amorphic materials scratch easily. (By definition "hardness" is resistance to identation. Just add movement and you have scratching.) Typically "hard" amorphic materials suffer from cracking. This is because hardness usually comes with decreased ductility. But fracture toughness is function of stiffness and ductility. So this material could(?!?) improve hardness while being about as easy cracking as old windshiels. This would be good idea as windshield is mostly mode of fracture limited design. (It matters more how your windshield breaks, than how much energy it takes to break it.)
To nitpick, the article uses the words 'tough', 'hard' and 'rigid' to describe this glass, though those all mean different things.
I'd suggest that all glass is both hard and rigid, so presumably 'tough' is what they're going for. If so, the glass should be able to withstand a large tensile force without fracture or permanent deformation.
'unbreakable' is also a little disingenuous. Everything is breakable, given a big enough hammer ;)
I'd suggest that all glass is both hard and rigid, so presumably 'tough' is what they're going for. If so, the glass should be able to withstand a large tensile force without fracture or permanent deformation.
'unbreakable' is also a little disingenuous. Everything is breakable, given a big enough hammer ;)
Don't think it's nitpicking at all. I came away unsure whether the new material is hard (scratch resistant) or tough (won't shatter when dropped). An article about a new material that doesn't make the distinction fails fundamentally.
You might find it interesting that toughness and "won't shatter when dropped" are different things.
Toughness(G) = slowly absorb energy without fracture.
Shattering is more dependable of:
Fracture toughness(Kc) = (E*G)^0,5
Where E = modulus. That explains why plastics with low E shatter easily while being tough. Metals have additional hardening methods that allow them to go beyond this rule.
PS. Your knowledge on the subject is already what I'd wish laymen had. So I really don't mean any offense.
Toughness(G) = slowly absorb energy without fracture.
Shattering is more dependable of:
Fracture toughness(Kc) = (E*G)^0,5
Where E = modulus. That explains why plastics with low E shatter easily while being tough. Metals have additional hardening methods that allow them to go beyond this rule.
PS. Your knowledge on the subject is already what I'd wish laymen had. So I really don't mean any offense.
To clarify, is fracture toughness the ability to withstand a sudden increase in energy?
Not really.. I had kind of error there. It's still often toughness when you wish to study how material reacts to sudden increases in (kinetic)energy.
Fracture toughness describes relation between maximum tension and maximum depth of pre-existing crack that still doesn't launch phenomena called "fast fracture".
https://en.wikipedia.org/wiki/Fast_fracture
It's highly relevant in many cases, because most real world materials have microscopic cracks. And because the load where fast fracture might happen is often lot smaller than yield load.
Curiously Charpy impact test still indicates more toughness than fast fracture. But it's never used to quantify toughness in real life.
https://en.wikipedia.org/wiki/Charpy_impact_test
Thanks for that comment. I need to clear this stuff bit more in my head.
Fracture toughness describes relation between maximum tension and maximum depth of pre-existing crack that still doesn't launch phenomena called "fast fracture".
https://en.wikipedia.org/wiki/Fast_fracture
It's highly relevant in many cases, because most real world materials have microscopic cracks. And because the load where fast fracture might happen is often lot smaller than yield load.
Curiously Charpy impact test still indicates more toughness than fast fracture. But it's never used to quantify toughness in real life.
https://en.wikipedia.org/wiki/Charpy_impact_test
Thanks for that comment. I need to clear this stuff bit more in my head.
None taken, thanks for the info!
> Everything is breakable, given a big enough hammer ;)
Or time alone with my daughter! "child-proof" isn't a reassurance, it's a challenge
Or time alone with my daughter! "child-proof" isn't a reassurance, it's a challenge
So many of us can identify with that, and so well stated!
They provided technical terminology when they explained that its Young's modulus is comparable to steel and iron. I agree that 'unbreakable' is clickbait even if it is quoted.
That still doesn't mean anything useful. That's just a measure of how much it changes shape per unit force in its elastic phase. It gives no indication about how far it can go changing shape in a reversible, elastic manner before it starts to yield and undergo permanent deformation.
Now a stress-strain curve on the other hand, THAT would be useful.
Now a stress-strain curve on the other hand, THAT would be useful.
Yeah, the only justification for 'toughness' was the Young's modulus, which does not tell you how resistant it is to breaking at all. And by that measure, sapphire [1] is 2.5 times tougher than steel [2].
[1] E = 7.4e7 psi (http://rubicontechnology.com/company/sapphire)
[2] E = 2.9e7 psi (https://en.wikipedia.org/wiki/Young%27s_modulus)
[1] E = 7.4e7 psi (http://rubicontechnology.com/company/sapphire)
[2] E = 2.9e7 psi (https://en.wikipedia.org/wiki/Young%27s_modulus)
I wonder if it's safe to smoke out of.
COnsidering what it's made of, I imagine it has some pretty amazing thermal properties.
aluminum is a known neurotoxin
Only at very high concentrations: Adverse neurological effects have been observed in rats and mice at doses of 100–200 mg Al/kg/day, while the USDA limit is 0.10–0.12 mg Al/kg/day for adult (25–30- and 70+-year-old) males and females. Aluminum is the 3rd most common element in the Earth's crust and humans have evolved given a certain level of environmental exposure. (http://www.atsdr.cdc.gov/toxprofiles/tp22-c2.pdf)
But is it as scratch resistant as hardened glass? Having glass that doesn't fracture when dropped is nice, but not if it means it gets scratched up from the keys in my pocket.
It's hard to imagine how a gas-based "containerless processing system" will lend itself to producing the thin, uniform sheets of glass for windows or complex shapes like tableware.
It's a cool prototype, but figuring out how to produce at scale is often the hard part.