The question of whether tungsten is the strongest metal is complex because “strength” is not defined by a single property in materials science. Tungsten, represented by the chemical symbol W and atomic number 74, is famous for its extreme physical properties. It stands out among all pure metals, but when compared to modern alloys and non-metallic materials, the picture becomes more nuanced. This metal holds several records, but its overall rank depends entirely on the specific type of force or condition being measured. The true nature of tungsten’s performance can only be understood by clarifying the metrics used to define a material’s strength.
Defining Material Strength
Materials scientists use several distinct metrics to quantify a material’s ability to resist different types of stress. One of the most common measurements is Tensile Strength, which measures a material’s resistance to breaking when pulled apart. This metric is often expressed as the maximum amount of stress a material can withstand before fracturing.
A closely related property is Yield Strength, which defines the point at which a material begins to permanently deform. If the applied force exceeds the yield strength, the material will no longer return to its original shape once the stress is removed. This value is critical for engineering applications where plastic deformation must be avoided.
Hardness is a separate property, focusing on a material’s resistance to localized surface deformation, such as scratching, indentation, or abrasion. Hardness is commonly measured using scales like Rockwell or Vickers, where a diamond indenter is pressed into the surface under a controlled load.
Finally, Toughness describes a material’s ability to absorb energy and deform plastically before fracturing. A material that is tough will resist the spread of a crack, while a material that is merely hard may be brittle and shatter upon impact. These four properties—tensile strength, yield strength, hardness, and toughness—rarely peak in the same material, making the concept of “strongest” context-dependent.
Tungsten’s Unique Characteristics
Tungsten earns its reputation for strength due to an unmatched combination of extreme physical properties. It possesses the highest melting point of any pure metal, reaching approximately 3,422 degrees Celsius, giving it tremendous heat resistance. This characteristic is a direct result of the strong covalent bonds formed between its atoms.
The metal also exhibits a remarkably high density, weighing in at about 19.3 grams per cubic centimeter, comparable to that of gold. This extreme mass contributes to its performance in applications requiring high inertial mass or radiation shielding. Tungsten’s stiffness, measured by its high modulus of elasticity, is also considerable, indicating its strong resistance to elastic deformation.
In terms of pure metallic strength, tungsten holds the record for the highest tensile strength of any pure element at room temperature. Furthermore, it retains its mechanical strength better than most other metals at extremely high operating temperatures, specifically above 1650°C. While pure tungsten is intrinsically hard, its polycrystalline form is often brittle, meaning it lacks the toughness to absorb significant impact energy without fracturing.
Comparing Tungsten to Other Contenders
When tungsten is compared against non-pure materials, its status as the strongest becomes less certain. For sheer tensile strength, advanced alloys often surpass pure tungsten. For instance, some grades of maraging steel, which are complex iron-nickel alloys, can achieve ultimate tensile strengths exceeding 2,000 megapascals (MPa). This figure is substantially higher than the maximum tensile strength of pure tungsten, which is typically closer to 1,510 MPa.
In the category of hardness, tungsten also loses its top spot to non-metallic materials and certain compounds. While pure tungsten is hard, the alloy tungsten carbide is significantly harder, making it the preferred material for cutting tools. However, even tungsten carbide is surpassed by ceramics like cubic boron nitride (cBN) and, ultimately, by diamond, the hardest known material. Cubic boron nitride, which has a Vickers hardness well over 4,000 HV, is routinely used to machine materials that tungsten carbide cannot effectively cut.
Tungsten’s true dominance lies in its heat resistance and density. No other metal comes close to its melting point, confirming its status as the most refractory pure metal. Therefore, while tungsten may be outclassed in tensile strength by specialized steel alloys and in hardness by ceramics, its overall performance under conditions of extreme heat and stress remains exceptional.
Practical Applications of Extreme Strength
The unique combination of high melting point, density, and hardness translates tungsten’s scientific properties into specific, high-performance industrial applications. Its ability to withstand extreme heat with minimal evaporation made it the standard material for the coiled filaments in incandescent light bulbs for over a century.
Due to its exceptional hardness and resistance to wear, tungsten carbide, an alloy of tungsten and carbon, is widely used in the manufacturing of high-speed cutting and drilling tools. These tools are used in mining, metalworking, and construction to machine other hard materials efficiently. They maintain their sharp edge and structural integrity even when generating intense friction and heat.
Tungsten’s high density is leveraged in applications requiring concentrated mass and kinetic energy. This includes its use in:
- Counterweights.
- Radiation shielding in medical and industrial settings.
- Armor-piercing ammunition.
In the military context, the density and momentum of tungsten projectiles allow them to penetrate thick armor plating without the use of explosive charges.