Tungsten is a benchmark for extreme material properties, known for its use in high-performance applications. This refractory metal has the highest melting point of all pure metals, an impressive tensile strength, and is often alloyed into tungsten carbide for its extreme hardness. In materials science, the term “stronger” is not singular. Comparing materials to tungsten requires clarifying the metric: scratch resistance, resistance to being pulled apart, or stability under extreme heat.
Defining the Metrics of Strength
The comparison of material strength relies on three distinct properties. Hardness measures a material’s resistance to permanent deformation, such as scratching or indentation, and is often quantified using the Vickers scale. Tungsten carbide (WC) is a common industrial standard, exhibiting a high Vickers hardness value of approximately 2,400 HV.
Tensile strength defines the maximum stress a material can endure while being stretched or pulled before it breaks. Pure tungsten has the highest tensile strength of any pure metal, especially at high temperatures. The third property, thermal resistance, is measured by the melting point, which for pure tungsten is 3,422°C (6,192°F).
Materials That Surpass Tungsten in Hardness
Materials with different crystal structures significantly surpass tungsten carbide in resistance to scratching and indentation. The benchmark for ultimate hardness is diamond, which ranks a perfect 10 on the Mohs scale and achieves a Vickers hardness of approximately 10,000 HV. Diamond’s superior hardness is due to its densely packed, three-dimensional lattice structure of carbon atoms held together by strong covalent bonds.
Cubic Boron Nitride (cBN) is the second hardest material, with a Vickers hardness ranging from 4,500 to 5,000 HV, nearly twice as hard as tungsten carbide. The cBN structure features a cubic lattice where boron and nitrogen atoms alternate, forming strong covalent bonds. This superhard material is valuable for machining hardened steel and other ferrous metals because, unlike diamond, cBN resists chemical reactions with iron at high temperatures.
Materials like Boron Carbide (B4C) also exceed the hardness of tungsten carbide, with Vickers values around 3,000 HV, positioning them for applications like body armor and specialized abrasives. These ultra-hard materials rely on tightly bound, complex crystal structures that make them highly resistant to any penetrating force.
Materials That Surpass Tungsten in Tensile Strength
While tungsten possesses excellent tensile strength among metals, it is easily surpassed by materials engineered at the nanoscale, which capitalize on the strength of primary chemical bonds. Graphene, a single layer of carbon atoms arranged in a honeycomb lattice, is a prime example. It exhibits a tensile strength approximately 200 times greater than that of structural steel, estimated at 130 gigapascals (GPa), which is orders of magnitude higher than even the strongest forms of tungsten.
Carbon Nanotubes (CNTs) similarly derive their strength from the sp2 covalent bonds between carbon atoms arranged in a cylindrical structure. This molecular architecture results in a material with a high strength-to-weight ratio, capable of enduring immense pulling forces before breaking. These carbon-based materials achieve their strength by exploiting the fundamental force of chemical bonding directly, without the structural imperfections common in bulk metals.
These materials are not used for applications requiring high hardness like cutting tools, as their strength is primarily directional. Tungsten remains the preferred material for high-force applications requiring bulk stability, density, and resistance to compression.
Materials That Surpass Tungsten in Thermal Resistance
Tungsten holds the title for the highest melting point of any elemental metal, yet several non-metallic compounds and ceramics are engineered to withstand even greater thermal extremes. This category is dominated by refractory compounds, which are materials that retain their strength and form at extremely high temperatures. The most heat-resistant material yet tested is Tantalum Hafnium Carbide (Ta4HfC5), a ceramic alloy.
This compound has demonstrated a melting point of approximately 4,215°C (7,619°F), significantly higher than pure tungsten’s 3,422°C. The exceptional thermal stability of Ta4HfC5 is a result of strong, highly stable covalent and ionic bonds within its complex crystal lattice.
These refractory carbides are pursued for use in the most demanding high-temperature environments, such as the leading edges of hypersonic vehicles and components within advanced nuclear reactors. These specialized materials maintain their structural integrity where tungsten would begin to fail, making them indispensable in aerospace and thermal protection systems. The existence of these compounds underscores that a material’s superiority is defined entirely by the specific stress it is designed to resist.