Tungsten/Nickel/Iron (W 95/Ni 3.5/Fe 1.5) is a high-density alloy valued for its exceptional mechanical strength, ductility, and corrosion resistance. Composed of 95% tungsten, 3.5% nickel, and 1.5% iron, this material combines the superior density and hardness of tungsten with the toughness and malleability imparted by the Ni–Fe matrix, making it a preferred choice for structural and radiation-shielding applications (Ekbom, 1991; Lassner et al., 2000).
Material Overview
Physically, the alloy exhibits a high density of approximately 18.0 g/cm³, providing significant mass within compact geometries — a key requirement in counterweights, radiation shielding, and kinetic energy penetrators. The alloy also demonstrates excellent mechanical integrity, with an ultimate tensile strength of around 136,900 psi (945 MPa), a yield strength of 92,500 psi (638 MPa), and an elongation at fracture of up to 28%, reflecting outstanding ductility and resilience (Sczerzenie & Zaleski, 1972).
Chemically, W 95/Ni 3.5/Fe 1.5 is stable and resistant to oxidation and corrosion. The tungsten phase provides rigidity and thermal stability, while the Ni–Fe binder phase enhances the alloy’s toughness, thermal conductivity, and ease of fabrication. This combination allows the material to perform reliably in both ambient and extreme environments, including high-radiation and high-heat conditions (Googin et al., 1961; Alam & Odette, 2023).
Microstructure and Fabrication
The alloy is typically produced through liquid phase sintering, where nickel and iron form a transient liquid that dissolves tungsten grains. Upon cooling, the tungsten reprecipitates as rounded grains within a Ni–Fe–W solid solution matrix, resulting in a uniform, ductile microstructure. This process significantly improves ductility compared to pure tungsten, which is inherently brittle at room temperature (Watts, 1969; Spencer & Mullendore, 1989).
The microstructure’s balance between solid tungsten particles and a continuous metallic matrix ensures fracture toughness values up to 80 ± 8 MPa√m, a notable improvement over similar heavy metal alloys. This level of toughness is critical for applications exposed to cyclic or impact loading, such as military and fusion energy systems (Alam & Odette, 2023).
Applications and Advantages
Defense and aerospace applications. The high density and strength of W 95/Ni 3.5/Fe 1.5 make it a key material in armor-piercing penetrators, counterweights, and ballast systems where mass concentration and mechanical durability are essential (Sczerzenie & Zaleski, 1972).
Nuclear and fusion technology. The alloy’s excellent fracture toughness and thermal stability make it suitable for plasma-facing components in fusion reactors and for radiation shielding in fission systems. Its ability to resist cracking under high thermal stress enhances long-term performance (Alam & Odette, 2023).
Industrial tooling and high-stress components. Due to its resistance to wear, fatigue, and thermal degradation, this alloy is also used in high-pressure dies, vibration damping systems, and kinetic forming equipment.
Performance Benefits
- Extremely high density (~18.0 g/cm³) for compact, mass-intensive applications.
- High tensile strength (≈136,900 psi) and yield strength (≈92,500 psi).
- Superior fracture toughness (~80 MPa√m) and ductility (≈28% elongation).
- Excellent resistance to corrosion, oxidation, and thermal stress.
- Outstanding dimensional stability under mechanical and thermal load.
Goodfellow Availability
Goodfellow supplies W 95/Ni 3.5/Fe 1.5 in a variety of forms, including bars, rods, and machined components, for use in radiation shielding, aerospace structures, and advanced defense systems. The alloy’s combination of strength, toughness, and density makes it ideal for critical high-performance engineering applications.
Explore Tungsten/Nickel/Iron (W 95/Ni 3.5/Fe 1.5) and related high-density alloys in Goodfellow’s online catalogue: Goodfellow product finder.
References
- Googin, J. M., Harper, W. L., Neeley, A. C., & Phillips, L. R. (1961). Development of Ductile Tungsten Alloys.
- Ekbom, L. B. (1991). Tungsten Heavy Metals. Scandinavian Journal of Metallurgy.
- Alam, M. E., & Odette, G. R. (2023). The Comparative Strength and Fracture Toughness Properties of Commercial 95W-3.5Ni1.5Fe and 95W-3.5Ni1.5Cu Tungsten Heavy Alloys. Nuclear Materials and Energy. https://doi.org/10.1016/j.nme.2023.101467
- Sczerzenie, F. E., & Zaleski, F. I. (1972). High Density, High Ductility, High Strength Tungsten-Nickel-Iron Alloy & Process of Making Therefor.
- Watts, T. D. (1969). Properties of Tungsten and Tungsten Alloys for Reactor Shielding Applications.
- Spencer, J. R., & Mullendore, J. A. (1989). Tungsten Nickel Iron Alloys.
- Lassner, E., Schubert, W.-D., Lüderitz, E., & Wolf, H. U. (2000). Tungsten, Tungsten Alloys, and Tungsten Compounds. https://doi.org/10.1002/14356007.A27_229