For a layman, strength and hardness are basically the same thing, but for a material engineer these two are way apart. While the strength of any material indicates its resistance to deformation, the hardness denotes its scratch resistance capability in general. The strength of any material is measured by its tensile strength i.e. the resistive power of any material before breaking under continuous pressure.
Do you know what is the strongest material on the Earth? Well, if the answer is no, you have landed on the correct destination. We are presenting some of the strongest materials known to human-kind.
26. Human Bones
Mineralized collagen fibers in bone
Tensile strength: 130 MPa
Our bones might not be the strongest material in the natural world, but it’s still stronger than many other things. Bones in the our body not only protects human organs, but also helps produce white blood cells and store minerals and enable us to do work. As we know, the bones come in different shapes and sizes, and not all the bones in our body are strong. The hardest bone in a our body is femur or thigh bone.
25. Silicon carbide
Tensile Strength: 137.9
Silicon carbide is a semiconductor, comprised mainly of carbon and silicon, and occurs naturally as mineral Moissanite. It is widely used in the automotive industry (ceramic brake disks), electrical appliances and even in astronomy (mirror material in telescopes). It is also used to produce steel and graphene in large quantities.
24. Aluminium Alloy
Russian Mig–29 is partly made of Aluminium alloy
Tensile Strength: 300 MPa
While, aluminium alloys are predominantly made from aluminium, other elements such as copper, manganese, silicon and zinc are also found in substantial amounts. Basically, there are two type aluminium alloy available: casting alloys and wrought alloys, both of them are further subdivided.
Aluminium alloys are heavily used in the auto industry, especially in engines: crankcases and cylinder blocks have the weight advantage. While they are widely used in multiple industries, aluminium alloys are known for their low fatigue strength. Because they are highly susceptible to deform under high temperatures, sufficient cooling systems are important in automotive engines.
23. Monocrystalline silicon
Comparison of crystalline solar cell. Monocrystalline silicon on the right.
Tensile Strength: 350 MPa
Monocrystalline silicon or single crystal silicon is perhaps one of the most important substance of the new era, as it is the principle material for silicon chip sets for almost all electronic gadgets we see around us. It’s primary based on solid, smooth silicon unbroken to its edges, and free of any grain boundaries.
Tensile Strength: 350 MPa
Cupronickel is mainly composed of nickel, iron, manganese and of-course copper. It has a high resistance to corrosion and macrofouling (accumulation of unwanted substance, organic/inorganic), a decent thermal conductivity, ductility and superior tensile strength. Due to its high corrosion resistance, cupronickel is widely used in shipping industry to build hulls and propeller of small fishing boats.
21. High Brass
Cracking in brass caused by ammonia attack
Tensile Strength: 500 MPa
High brass is one of the types of brass alloys which is mainly composed of 65% copper and 35% zinc along with many trace element such as lead, aluminium and manganese. Due to its high tensile strength and corrosion-resistant property, it’s mostly used used in springs, screws, and rivets.
20. Palladium Microalloy glass
Micrograph of palladium-based metallic glass shows extensive plastic shielding of an initially sharp crack. Image Courtesy: Berkeley Lab
In 2011, material researchers from the California Institute of Technology along with Berkeley Lab developed a new type of high tolerant metallic glass that is way tougher than steel. Like its name suggests, this metallic glass is made of palladium, a shiny metal with a high stiffness ratio that act against the brittleness of glass but maintain its strength.
19. Titanium Alloy
Flat-12 Colombo in a 1991 Testarossa
Tensile Strength: 1000 MPa
Titanium alloys are the reason why we have strong yet light sports cars, huge airplanes, missiles and rockets, where low weight, high durability and resistance is a must.
They are extremely light weight and have high corrosion resistance property, which is one of the main reasons why they constitute a large part of propeller shafts and other parts of ships and boats that are continuously exposed to water. However, they are largely limited to military use and high-end industry due to its high cost raw materials and product limitation.
18. Liquidmetal Alloy
Tensile Strength: 550- 1600 MPa
Don’t get fooled by its name, as liquidmetal alloys have high tensile strength, adequate resistance to corrosion and they are not liquid in the room temperature. Developed by researchers at the Caltech University, liquidmetal alloys are more flexible in terms of casting into complex shapes without finishing due to their gradual viscosity level decrease while being heated. They were commercially introduced for the first time in 2003, and are now used in golf clubs, cell phone covers and watches.
17. Spider Silk
Female Argiope bruennichi wraps her prey in silk
Tensile Strength: 1000 MPa
You have probably seen a spider’s web and know how a spider uses it to catch prey and protect their offspring. They also use their silk as a medium to float through the air while running away from predators. But do you know that their silk is also one of the toughest naturally occurring material on the Earth.
The strength of spider silk varies from species to species and several other external factors such as temperature and humidity during the time of testing. On a comparative scale, the strongest spider silk is almost as strong as premium quality steel while it has the half of the strength of Kevlar
16. Tungstun Carbide
Tungsten carbide spikes Image Courtesy: Hustvedt
Tensile Strength: 1510 MPa
Tungstun carbide compound is made of equal parts of carbon and tungston atoms. It is mostly used in heavy industrial tools such as cutting instruments and high caliber bullets. Although, tungsten carbide is principally a fine gray powder, it can be squeezed to abrasives and jewelry. On an average, tungstun carbide is much more stronger than the steel. It has a Young’s modulus of 700 (high end) GPa and density somewhere between that of lead and gold.
15. UHMWPE Fibers (Dyneema)
Tensile Strength: 2300–3500 MPa
Dyneema is a strong, ultra lightweight polyethylene fiber, which is mostly used as composite plates of personal and vehicle armour. It’s also used in climbing equipments, fishing ropes, bow strings etc. It has a total yield strength of 2.4 Gpa and a low specific gravity of 0.97 g/cm3.
14. Glass Fiber
Bundle of Glass FIber
Tensile Strength: 3450 MPa
For decades, researchers have toyed with the idea of making fine glass material, but it only became a reality in the year 1932, Russell Slayter constructed a similar material and used it as thermal insulation for buildings. Glass fiber has comparable mechanical properties like polymers and carbon fiber. Even though, glass fibers are not as strong as carbon fibers, it is much cheaper and less brittle when used in different composites.
13. Maraging steel
Tensile Strength: 2693 MPa
Maraging steels are a special variety of ultra high strength steels, which derive strength from intermetallic compounds rather than carbon. They are known for their strength and toughness, without losing ductility. One of the principle elements used in maraging steel is 25% mass fraction of Nickle, while cobalt and titanium are also used in combination.
Its better weight to strength ratio than most of the other steels, allows maraging to be widely used in missiles and rocket skins. The steel is also suitable for important engine components, such as crankshafts and gears. One more popular use of maraging steel is in the blade used in a game of fencing.
Tensile Strength: 2800 MPa
Diamond is the hardest known natural mineral found on Earth according to Mohs scale. Diamond hardness depends on its purity and the hardest diamond can only be scratched by other diamonds. Some blue color diamonds are natural semiconductors, some are electrical insulators and rests are electric conductors. Approximately 26000 kg of diamonds are mined annually, out of which 50% diamonds originate from Central and Southern Africa.
Molecular structure of Vectran
Tensile Strength: 2850–3340
Solely produced by Japanese Kuraray corporation, Vectran is a chemically stable polyester with high strength and thermal durability. They are mostly used as an enforcement for electrical cables, ropes and are also deployed as one of the composite materials for high-end bike tires etc. One downside of Vectran is that despite of its higher tensile strength it tends to experience fractures.
Tensile Strength: 3,620 MPa
Kevlar was first used in the 1970s, not in military equipment but as a replacement of steel in racing tires. Currently, Kevlar has many applications, ranging from bicycle tires and racing sails to bulletproof vests, because of its high tensile strength-to-weight ratio; by this measure it is 5 times stronger than steel.
9. Patella vulgata
Tensile Strength: 3000-6500 MPa
Commonly known as European limpet, it’s a species of sea snails mostly found in Western Europe. Their teeth is one of the strongest material discovered till date. A study in 2015, published in the Royal Society Journal indicated that a tooth of a European limpet can be stronger than spider silk, which is officially the strongest naturally occurring material on Earth. Their tensile strength is compared to that of commercial carbon fibers.
Originally made from carbon nanotubes, buckypaper or buckytubes are believed to be about 50,000 times thinner than an average human hair, and 500 times stronger than steel. One more interesting characteristics of buckypaper is, it can disperse heat like brass or steel and it could conduct electricity like copper or silicon.
Tensile Strength: 5800 MPa
Zylon is exclusively designed and developed by SRI International as a special variety of thermoset liquid-crystalline polyoxazole. It’s 1.6 times stronger than Kevlar, and just like Kevlar, Zylon is used in a number of applications that require very high strength with excellent thermal stability. Tennis racquets, table-tennis blades and snowboards, are some its known applications.
6. Carbon Fiber
Tensile Strength: 5800
Carbon fibers are about 5–10 micrometres in diameter and composed mostly of carbon atoms. They have several advantages over steel and alloys including high stiffness, high tensile strength, low weight, high chemical resistance, high-temperature tolerance and low thermal expansion.
These properties have made carbon fiber very popular in aerospace, military, civil engineering and sports industry. However, they are relatively expensive when compared with similar fibers, such as glass fibers or plastic fibers.
5. 3D Form of Graphene developed By MIT Engineers
Recently, a team of researchers at MIT has developed a lightweight material, which is believed to be one of the strongest man-made material on the Earth. Researchers discovered the material by compressing and fusing small pieces of graphene. The resulted material is sponge-like with a density of just 5% of steel but 10 times of its strength.
The two-dimensional form of graphene is believed to be the strongest of all known materials, and researchers are trying to discover ways to implement 3D graphene into commercial use.
4. Carbon Nanotubes
Tensile Strength: 11000–63000 MPa
Just like diamond and graphite, carbon nanotubes are one of the allotropes of carbon in cylindrical nanostructure. There exceptional strength and less weight is the reason why it’s valuable for the electronics industry and nanotechnology. Furthermore, due to their excellent thermal conductivity, electrical and mechanical properties, carbon nanotubes are basic to many industries.
Tensile Strength: +2800 MPa
Lonsdaleite, also known as the hexagonal diamond, was named in honor of Kathleen Lonsdale, a famous Irish crystallographer. Lonsdaleite is a naturally occurring mineral, forms when meteorites containing graphite strike the earth. The heat and stress resulting from the strike transform the graphite into diamond while retaining graphite’s hexagonal crystal lattice. It is believed that lonsdaleite is 58 percent harder than diamond.
2. Wurtzite Boron Nanotube
Tensile Strength: 33000
Wurtzite boron nitrite is one of the rarest substances in the world. They are either naturally found or manually synthesized. Various simulations showed that Wurtzite boron nanotubes can withstand 18 percent more stress than diamond. Naturally, these are produced during volcanic eruptions due to very high temperatures and pressure.
Image Courtesy: AlexanderAlUS
Tensile Strength: 130000 MPa
Graphene is perhaps the strongest material known to humans. It is basically composed of a single layer of carbon atoms arranged in a triangular lattice and it’s the basic structural element in charcoal, graphite and carbon nanotubes. Graphene is known for many unique properties; it’s a good conductor of heat and electricity while being transparent.
While it’s being produced in small quantities for over a century, the first isolated discovery of graphene was done by Andre Geim and Konstantin Novoselov in 2004, both of whom won the Nobel prize in physics for their contributions. Graphene’s massive tensile strength of 130000 MPa shows that it’s more than 200 times stronger than steel, and therefore it’s vastly used in aerospace and automotive industries.