What Is the Strongest Metal for 3D Printing?

When looking for the strongest metal for 3D printing, it’s crucial to understand that “strongest” can mean different things. Are you searching for the highest ultimate tensile strength, exceptional performance at high temperatures, or the best strength-to-weight ratio? The ideal material for your project will depend on the specific application you have in mind. This guide will walk you through the top contenders for the strongest 3D printing metals, helping you make an informed decision for your manufacturing needs.

The Strongest Metals for 3D Printing

Let’s take a closer look at the unique characteristics of these powerful 3D printing metals.

Maraging Steel (18Ni-300)

Maraging steel, specifically the 18Ni-300 grade, is a top-tier choice for applications demanding exceptional hardness and strength. After undergoing heat treatment, this steel can achieve an ultimate tensile strength (UTS) of around 1800 MPa.

• Pros:
  • Extremely high strength and hardness.
  • Good machinability in the annealed state.
  • Excellent dimensional stability during heat treatment.
• Cons:
  • Lower corrosion resistance compared to stainless steels.
  • Higher cost than some other steel alloys.

Its remarkable properties make it a go-to material for high-performance tooling, injection molds, and aerospace components.

Custom β-Titanium Alloys

Research into custom beta-titanium alloys has led to groundbreaking developments in the strength of 3D printed materials. Scientists have engineered alloys that, after specialized heat treatments, can reach a UTS of over 1.6 gigapascals (GPa). These advancements are pushing the boundaries of what is possible with additive manufacturing. While still largely in the research and development phase, these custom alloys hold immense promise for future applications in sectors that require the utmost in performance and lightweighting, such as advanced aerospace and medical implants.

Inconel 718

Inconel 718 is a nickel-chromium superalloy renowned for its outstanding performance in extreme environments. It maintains its strength and corrosion resistance at both very high and very low temperatures, making it a versatile and reliable choice. Its UTS is approximately 1375 MPa at room temperature.

• Pros:
  • Excellent mechanical properties at a wide range of temperatures.
  • High resistance to oxidation and corrosion.
  • Good weldability.
• Cons:
  • Difficult to machine.
  • High material cost.

Inconel 718 is widely adopted in the aerospace industry for jet engine and gas turbine components, as well as in the energy sector.

Cobalt-Chrome

Cobalt-chrome alloys are celebrated for their impressive combination of strength, wear resistance, and biocompatibility. With a UTS typically around 1000 MPa, this material is a staple in the medical field for producing implants such as knee and hip replacements.

• Pros:
  • Excellent biocompatibility.
  • High corrosion and wear resistance.
  • Good strength and hardness.
• Cons:
  • Can be challenging to process and machine.
  • Concerns over potential long-term release of cobalt ions.

Its use extends to dental implants and high-wear industrial applications, where its durability is a significant asset.

Tungsten and Heavy Alloys

Tungsten boasts the highest melting point of all metals, making it and its heavy alloys ideal for applications involving extreme heat. While incredibly strong and dense, tungsten is also quite brittle at room temperature.

• Pros:
  • Exceptional high-temperature strength.
  • High density.
  • Excellent radiation shielding properties.
• Cons:
  • Brittle at low temperatures.
  • Difficult to machine and process.

These unique properties make tungsten a critical material for niche applications such as rocket nozzles, heating elements in high-temperature furnaces, and radiation shielding.

Strengths of Leading 3D Printing Metals

To provide a clearer overview, the following table summarizes the key mechanical properties of these top-tier metals.

Note: The properties listed are approximate and can vary based on the printing process, parameters, and post-processing treatments.

Factors Influencing Metal Strength in 3D Printing

The final strength of a 3D printed metal part is not solely dependent on the material itself. Several factors throughout the manufacturing process play a critical role:

• Printing Technology: The method used, such as Selective Laser Melting (SLM), Direct Metal Laser Sintering (DMLS), or Electron Beam Melting (EBM), significantly impacts the microstructure and, consequently, the mechanical properties of the part. For instance, an SLM metal printer can produce highly dense and strong components.
• Post-processing and Heat Treatment: These steps are often crucial for achieving the desired strength. Heat treatments can relieve internal stresses, alter the crystal structure, and significantly enhance the mechanical properties of the printed part.
• Alloy Composition and Powder Quality: The precise composition of the metal alloy and the quality of the metal powder, including particle size and shape, are fundamental to the final part’s integrity and strength.

Choosing the Right Metal for Your 3D Printing Project

Selecting the appropriate metal requires a careful evaluation of your project’s specific needs. Here are some actionable steps to guide you:

1. Define Your Requirements: Clearly identify the primary performance criteria. Is it tensile strength, hardness, corrosion resistance, weight, or a combination of these?
2. Consider the Operating Environment: Will the part be subjected to high temperatures, corrosive substances, or significant stress?
3. Evaluate Printer Compatibility: Ensure that your chosen metal is compatible with your 3D printing equipment.
4. Factor in Post-Processing: Be aware of the necessary post-processing steps and their impact on the final cost and lead time.
5. Balance Performance and Cost: While high-performance metals offer exceptional properties, they also come at a higher price. Determine if the performance benefits justify the cost for your application.

Conclusion

The landscape of metal for 3D printing is rich with high-strength options, each with its unique advantages and ideal use cases. From the sheer power of maraging steel and the innovative potential of custom titanium alloys to the high-temperature resilience of Inconel and the biocompatibility of cobalt-chrome, the possibilities are vast. By understanding the key properties of these materials and the factors that influence their strength, you can confidently select the best metal to bring your high-performance 3D printing projects to life.