What is the world’s strongest metal? This is one of those questions that sounds simple enough but is actually quite complex. When it comes to metal, making direct comparisons based on strength doesn’t work. Why? First of all, because there isn’t a single, universal scale for strength. Although there are several different definitions of strength, including hardness, yield strength, and compressive strength, this article focuses mainly on tensile strength, which is the force required to stretch an object or pull it apart.
Tensile strength refers to a material’s ability to resist tension. In other words, it looks at the amount of strength required to stretch or pull something apart. A material with low tensile strength would pull apart more easily than a material with high tensile strength.
Compressive strength refers to a material’s ability to withstand being squeezed together (compressed). To test compressive strength, an external force places pressure upon a material, tracking to what degree the material can resist size reduction. A widely accepted test for compressive strength is Mohs Hardness Test. The test relies on a scale which rates minerals from 1-10, or softest-hardest
Yield strength refers to a material’s ability to withstand permanent deformation or bending. It’s a way of testing the elastic limit of a given material. Usually determined via a bend test where two ends of a beam or bar are gripped and stress is applied. The intent is to discover how much stress it requires to exceed the material’s yield point, or the point at which the material will not return to its original shape upon removal of the stress.
Impact strength refers to a material’s ability to withstand a blow without fracturing or shattering. In other words, it’s a method for determining the limit of how much energy a material can absorb via impact.
Since a metal’s strength depends on multiple factors, there isn’t a simple answer to the question, what is the strongest metal? Instead, there are several metals that are known to be among the strongest. I’ve chosen to list them in alphabetical order. Please do not take the following list’s order as a ranking.
Chromium metal rates highest on the Mohs hardness scale, but it is brittle, and must be mixed with other metals for greater tensile strength, for example, in stainless steel.
Tungsten has the highest tensile strength of any pure metal – up to 500,000 psi at room temperature. Even at very high temperatures over 1,500°C, it has the highest tensile strength. However, tungsten metal is brittle, making it less useable in its pure state.
Pure titanium has a higher tensile strength than standard steel, but it is less dense, giving it a very high strength-to-weight ratio. However, steel alloys are stronger than pure titanium.
Inconel is an alloy of nickel and chromium, with several other elements, such as molybdenum. Inconel comes in several different grades, and is known for high strength at high temperatures, as well as corrosion resistance.
Steel itself is an alloy of carbon and iron. Alloys of steel with additional elements added, such as carbon (tool) steel and stainless steel can be crafted that are much stronger than standard steel. Each alloy is specifically designed to optimize different properties for different applications. Tensile strength, corrosion resistance, hardness, impact resistance, yield strength, and other properties, depend on the alloying elements chosen and the processes used.
Scientists continue to develop and test new alloys with even greater properties. In recent years, several different university research groups have announced new types of magnesium alloys that exhibit exceptional strength, along with light weight and high corrosion resistance. These new materials are already being used in smartphone and laptop cases, electric batteries, and medical implants.