Whether you're trying to dig for diamonds or drill to the center of the earth or simply trying to cut into one of my mom's over-baked cakes. You're going to want a pretty strong material, but assuming that there's no unobtainium or adamantium lying around, where can you turn just.

What is the strongest stuff that we can get our hands on?

Well, turns out it really depends on what you're trying to do, because materials can be strong in different ways depending on which direction the stress is applied.

In if we take something and squeeze it, we are subjecting it to compressive stress and to withstand that stress without breaking it needs a large enough compressive strength. If instead of squeezing we pull it in opposite directions, we are subjecting it to tensile stress and the material must have enough tensile strength to resist the force.

In real-life situations through objects are subjected to a combination of these stresses, as well as shear stress, which comes from forces sliding past each other to be of any use to the heroically minded. The world's strongest material must be able to withstand all these kinds of forces.

In reality, though most materials are either high in tensile strength or compressive strength, for example, it's fair to say that concrete is pretty strong. They certainly thought so in the 60s, opting to build basically everything out of that gray Wonder stuff, and it does have a pretty high compressive strength. Able to withstand up to 14 mega Pascal's of pressure. This is what you get if you balanced 325,000 London buses on a phone box. But when it comes to tensile and flexural strength, that's its resistance to stretching and bending, it's around eight times weaker and will fail when exposed to a stress of just 5 mega Pascal's.

To properly understand what makes something strong, we need to delve into the microscopic and see exactly what it is that holds stuff together. You might remember from your school chemistry lessons that the molecules in a material are held together by bonds. There are lots of different types of bonds: ionic, covalent, metallic, but they all basically work in the same way, to strongly attract atoms to each other. It's these bonds that help a substance hold its structure. Without them, you'd have gas.

So if bonds are what hold solids together, it makes sense to say that the more bonds the stronger the solid will be, right? Well, yeah, kinda. Kinda because there is a limit to how many bonds every atom can make.

Carbon, for example, can only bond with four other atoms. Oxygen only with two. So as you can't have an unlimited number of attachment points between atoms, the arrangement of the bonds.

The atomic structure of a substance becomes very important. Take graphite and diamond, both are made of pure carbon, but their atomic structure is very different. Graphite is the soft black stuff in pencil lead and it has its carbon atoms arranged in flat sheets which can easily slide over each other. When it's exposed to shear stress like drawing a pencil across a piece of paper, those super weak bonds break and sheets just get wiped off.

In contrast, a diamond which many people recognize as one of the world's hardest materials, and more on that later. That has its carbon atoms held together in a regular 3d pattern, an interlocking tetrahedral structure, now with each atom locked tightly in the structure is brilliant at distributing force: there are no weak links to limit material strength.

 So, in our search for the world's strongest material, should we be looking at the atomic scale for a perfectly even crystal structure to share the load when force is applied, well it makes sense but no sorry. In reality, a material can actually be made stronger by the presence of imperfections and defects in that atomic order. Any breaks in the perfect order of bonds can help to stop any cracks or deformation. In fact, several techniques for developing stronger and stronger materials have attempted to do just that, introduced imperfections through processes such as grain boundary and solid solution strengthening.

Back to Diamond then. If it's so hard then why hasn't anyone had the genius idea of making indestructible diamond body armor or building towering diamond skyscrapers. Well, even if you manage to get enough diamonds together and do such a thing, you'd be sorely disappointed. While the diamond is extremely strong, not very tough. Plus, it's incredibly brittle, which means that just a relatively gentle hammer strike would be all that you've been needed to shatter the entire structure. While strength is defined as the maximum stress that material can support before starting to break. Toughness describes a material's ability to absorb energy and deform before breaking.

In most materials you can either have strength or toughness just like a diamond which is very strong but not very tough, it will break really easy when the right kind of stress is applied, or like aluminum which is tough and can deform easily without breaking which nobody in their right mind would describe as strong.

So for all practical purposes, the world's strongest material needs the best of both worlds, strength, and toughness which given that as one increases the other tends to decrease, it's no easy task.

So what can we do? Well, as with all great innovations like penicillin, gliders, and leopard print jeggings. Material scientists turn to the natural world for inspiration, where geology has failed us in providing the frankly inferior diamond. Biology can pick up the slack. Deep in the Madagascan jungle, Darwin's bark spider is casually producing one of the world's strongest materials out of its backside. From spiracles on its abdomen, this spider produces silk, whose extraordinary composition achieves that holy grail of material strength and is both strong and tough. In fact, this dragline silk which is produced by the spider as the first anchoring strand of one of the largest webs in the world has a tensile strength that is several times that of Steel. All while being only 1/10 of the width of a human hair.

Exactly why it is so strong? is still poorly understood, but we do know that is made up of two different types of proteins. The first forms an amorphous stretchable matrix, which gives its elasticity, and the other has a form of pleated crystalline structure, which gives it its strength. The organization of the two types of proteins within the Strand makes it a biological marvel, and one that scientists have been very keen to develop.

But you know what we can do better than that. Remember the graphite in our pencil lead, just that slight pressure and a sideways swipe is all it takes to shear off layers of carbon atoms, it isn't strong and it isn't tough but keep sliding those layers off separating the ultrafine leaves off the graphite book and you can find yourself with a substance that is quite remarkable.

You see when you're left with just a single sheet of carbon atoms all bonded to each other in a hexagonal pattern; you don't have graphite anymore; you have graphene, and graphene is being widely proclaimed as one of the strongest materials have ever been made.

First developed in 2004, it also achieves the highly desired combination of strength and elasticity. In fact, it's able to stretch by up to 25% of its original size before it breaks-and it's able to withstand an impressive amount of localized force, a thin film requires a pressure equivalent to an elephant standing on a pencil point before it breaks. With such impressive credentials, you'd think that graphene would have been snapped up for all manner of engineering and defense applications, but in actual fact, no one really knows what to do with it. Most ideas involve combining graphene with another material such as plastic or rolling it up into fibers, but at the moment it is so costly to separate individual atom thin layers of carbon that such composite materials are not economical to develop.

So, whether you choose to get your super-strong material out of spider's butts. All through expensively deconstructing a pencil, it's clear that scientists are still some way from achieving true indestructibility. This is just as well because as soon as they do they're probably going to start making those fiddly plastic packets at graphene and it's going to be no hope for any of us.

 

I want to know if you had access to the world’s strongest material, what would you do with it.

 

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