Microscopic view of iron and nickel atoms interacting in tungsten carbide matrix.

Unlock Stronger Materials: The Surprising Science of Iron and Nickel in Hardmetals

Soraya Malik in Tech & Innovation August 2025 • 4 min read.

"Could iron replace nickel in the creation of super-strong hardmetals? A new study reveals the potential for stronger, more cost-effective materials."

In industries ranging from oil drilling to advanced manufacturing, the demand for exceptionally durable materials is constant. These materials, often referred to as hardmetals, are critical for tools and components that must withstand extreme conditions. Traditionally, hardmetals have relied on a combination of tungsten carbide and metals like nickel and cobalt to achieve their toughness. However, researchers are constantly seeking ways to improve performance and reduce costs.

A recent study published in the 'International Journal of Refractory Metals and Hard Materials' has explored the potential of using iron as a substitute for nickel in hardmetals. This research delves into how iron influences the structure and mechanical properties of tungsten carbide composites, opening doors to new material designs with enhanced capabilities.

This article breaks down the key findings of the study. It explains the implications for industries looking for stronger, more cost-effective materials. We'll explore the innovative techniques used and the potential benefits of incorporating iron into the hardmetal mix.

The Iron-Nickel Dynamic: A Microscopic Look

Microscopic view of iron and nickel atoms interacting in tungsten carbide matrix.

The study focuses on spontaneous infiltration, a process where molten metal is drawn into a powder compact, creating a dense, solid material. Researchers compared hardmetals produced using nickel and iron infiltration methods. They examined the resulting microstructures using advanced techniques like scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). These methods revealed how nickel and iron interact with tungsten carbide at a microscopic level.

One key finding was that both iron and nickel partially dissolve into the metallic binder during infiltration. This binder, often a copper-based alloy, acts as the glue holding the tungsten carbide particles together. The researchers observed that iron and nickel exhibit a chemical affinity, leading to the formation of unique microstructures. For example, iron promotes the creation of (Fe, Ni) solid solutions and FeNi3 intermetallic precipitates at the interface between the tungsten carbide particles and the matrix.

Enhanced Hardness: The presence of these iron-nickel compounds significantly increases the hardness of the material.
Improved Elastic Modulus: The diffusion of iron into the matrix leads to the formation of tiny precipitates of α-Fe and Ni3Sn, boosting the material's stiffness.
Cost-Effectiveness: Iron is more abundant and cheaper than nickel, potentially lowering the cost of hardmetal production.
Performance: The increased elastic modulus of the material driving to an increase of about 30% in its elastic modulus, and without appreciable effect in the hardness observed..

These microstructural changes translate into improved mechanical properties. The study found that the iron-infiltrated hardmetals exhibited a higher elastic modulus, meaning they are stiffer and less prone to deformation under stress. This enhanced stiffness, combined with increased hardness, makes iron-based hardmetals promising candidates for demanding applications.

The Future of Hardmetals: A Shift Towards Iron?

This research provides a compelling case for further exploration of iron-based hardmetals. While challenges remain, the potential benefits are substantial. By optimizing the composition and processing techniques, engineers could unlock a new generation of high-performance, cost-effective materials for a wide range of industrial applications. As industries continue to push the boundaries of material performance, iron-based hardmetals offer a promising path forward.

About this Article -

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This article is based on research published under:

DOI-LINK: 10.1016/j.ijrmhm.2018.11.002, Alternate LINK

Title: Comparative Investigation Of The Ni And The Fe Effect On The Structure And Mechanical Response Of A Wc-W-Ni Hardmetal Obtained By Infiltration

Subject: General Medicine

Journal: International Journal of Refractory Metals and Hard Materials

Publisher: Elsevier BV

Authors: H. Bouchafaa, D. Miroud, S. Mato, Z. Boutaghou, B. Cheniti, F.J. Pérez, G. Alcalá

Published: 2019-02-01

Everything You Need To Know

What materials are traditionally used in hardmetals, and how might iron change this composition?

Hardmetals traditionally use tungsten carbide combined with metals like nickel and cobalt to achieve their toughness, making them suitable for demanding applications. However, research indicates iron may be a suitable replacement for nickel. Iron, when used in spontaneous infiltration process, promotes the creation of (Fe, Ni) solid solutions and FeNi3 intermetallic precipitates at the interface between the tungsten carbide particles and the matrix. The use of iron offers potential cost benefits due to its abundance and lower price compared to nickel.

What specific techniques were used to examine the microstructure of hardmetals made with iron and nickel?

The study utilized advanced techniques such as scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) to examine the microstructures of hardmetals produced using both nickel and iron infiltration methods. These methods allowed researchers to observe how nickel and iron interact with tungsten carbide at a microscopic level, identifying key differences in the resulting materials. These techniques make it possible to analyze chemical composition and elemental mapping.

How does using iron in hardmetals affect their mechanical properties, such as hardness and stiffness?

The study found that iron-infiltrated hardmetals exhibit a higher elastic modulus, indicating greater stiffness and resistance to deformation under stress. Furthermore, the presence of iron-nickel compounds increases the hardness of the material. These microstructural changes, such as the diffusion of iron into the matrix leading to the formation of tiny precipitates of α-Fe and Ni3Sn, translate into improved mechanical properties, making them attractive for demanding applications. There was an observed increase of about 30% in its elastic modulus.

Can you elaborate on the process of spontaneous infiltration and its importance in the creation of hardmetals?

Spontaneous infiltration is a process where molten metal is drawn into a powder compact, creating a dense, solid material. In the context of hardmetals, it involves infiltrating molten iron or nickel into a tungsten carbide powder compact. This process is crucial for creating the desired microstructure and mechanical properties in the final hardmetal composite. The metallic binder, which is often a copper-based alloy, acts as the glue holding the tungsten carbide particles together. The control and optimization of this process impacts the quality of the material.

What is the significance of (Fe, Ni) solid solutions and FeNi3 intermetallic precipitates in iron-based hardmetals?

The research highlights that using iron in hardmetals leads to the formation of (Fe, Ni) solid solutions and FeNi3 intermetallic precipitates at the interface between tungsten carbide particles. These iron-nickel compounds significantly increase the hardness and elastic modulus of the material. This suggests that optimizing the composition and processing techniques for iron-based hardmetals could unlock a new generation of high-performance, cost-effective materials for wide range of industrial applications. The presence of these compounds improves the overall performance and durability of the hardmetal.