AI-Designed 3D-Printed Steel: Ultra-Strong & Rust-Proof

Steel is one of the key materials of modern civilization. Its durability, ductility, and high strength make it vital in almost every aspect of our lives: manufacturing, transportation, construction, and energy.

Interestingly, steel is entirely recyclable, without losing its quality, strength, or structural integrity, making it critical for sustainable economic development.

In 2025, the world produced a total of 1,849.4 Mt (million tonnes) of crude steel, down from 1,882.6 Mt in the previous year. Data shows that China is the leading steel producer, followed closely by India and the USA.

Employing millions of people globally, the steel industry serves as a key economic driver.

But what exactly is it? Steel is an alloy, a mixture of two or more elements. More specifically, steel is composed of a metallic element iron (Fe) and small amounts of non-metallic carbon (C) as well as some additional elements, such as manganese (Mn), phosphorus (P), sulphur (S), silicon (Si), oxygen (O), chromium (Cr), or nickel (Ni) to enhance the material’s strength, toughness, and corrosion resistance.

So, there isn’t just one type of steel; there are hundreds of different grades of steel with different chemical and physical properties.

As for how steel is produced, the blast furnace-basic oxygen furnace (BF-BOF) and electric arc furnace (EAF) methods are usually used. The key difference between the two is in the type of raw materials they consume.

The BF-BOF method mainly uses iron ore, coal, and recycled steel, while the EAF method predominantly utilizes recycled steel and electricity.

While the steel industry has made significant efforts to reduce environmental pollution over the past few decades, the dominant method for producing steel from iron ore still relies on fossil fuels as reducing agents. But the implementation of new technologies in pilot and commercial-scale facilities is helping make a shift toward low-carbon steel production.

Moreover, scientists are continually working to create more eco-friendly steel with far greater properties than the existing one.

For instance, super-strong steel, often classified as Advanced High-Strength Steel (AHSS) or Ultra-High-Strength Steel (UHSS), boasts yield strengths exceeding 550-1000 MPa. Research on this type of steel is driven by the need for lighter, safer, and more durable materials for industries seeking to improve efficiency and reduce carbon footprints.

To realize this kind of steel, scientists tend to manipulate the alloy’s nanoscale structure.

About a decade ago, a team from Pohang University of Science and Technology invented a steel alloy¹ that had the same strength-to-weight ratio as titanium, a super-strong metal used to construct missiles, jet engines, spacecraft, and medical implants, but for one-tenth of the cost.

Then, several years ago, scientists from Lawrence Berkeley National Labs and the University of Hong Kong made a super steel by “activating delamination toughening coupled with transformation-induced plasticity.”

Scientists are also working on rust-proof steel, which can help prevent structural failure and ensure durability in high-moisture environments.

That’s because steel is highly susceptible to rust. When exposed to moisture and oxygen, it begins to revert to its original form, i.e., iron oxide. Different protective coatings, such as paint or zinc galvanization, are used to overcome this problem. Chromium and nickel are also used to create stainless steel, which is much more resistant to corrosion, though it can still rust in specific, harsh conditions.

Scientists have now developed a new alloy with the help of artificial intelligence (AI) that not only increased the metal’s strength by 30% but also doubled its ductility and made it rust-proof. Also, this super steel can be 3D printed.

Additive Manufacturing as a Game-Changer for Steel Innovation

Additive manufacturing (AM), often called 3D printing, has gained widespread adoption over the last decade. It has progressed from a mere niche prototyping tool to a mainstream production method, actively used for mission-critical parts in the aerospace, automotive, and medical industries.

In this process, a 3D object is built by adding material layer by layer based on a digital model. It utilizes a range of materials, including plastics, polymers, and metals.

For researchers and companies, the biggest advantage of 3D printing technology is speed. Rapid prototyping reduces costs, accelerates development cycles, and allows for iteration.

Additionally, 3D printing is the most cost-effective manufacturing process for small production runs, eliminating the need for expensive machines and experienced technicians to operate them. There is also far less waste material as the part is built from scratch.

Then there’s the flexibility to create unique, complex, and custom parts from multiple materials. Meanwhile, the step-by-step assembly of parts in 3D printing enables consistency and higher quality.

Sustainability is yet another great benefit of 3D printing. One can develop the whole product by themselves, reducing the need for outsourcing.

For steel manufacturers, this manufacturing technique significantly reduces development time and material waste while enabling them to experiment in-house and conduct prototype tests more quickly. It also allows engineers to rapidly validate new alloy compositions, optimize performance, and move from design to production without relying on expensive traditional tooling or outsourced fabrication.

Compared to traditional manufacturing technologies, AM has special characteristics², such as layer-by-layer accumulation, material interactions, high cooling rates, and cyclic heating. These features result in a unique microstructure, including fine grains, high-density dislocations, a metal-cell structure, and a phase composition, which impart remarkable mechanical properties to ultra-high-strength steels.

When it comes to 3D printing ultra-high-strength and ductile steel (UHSDS), which boasts exceptional mechanical properties, it has shown great applicability in sectors such as aerospace, automotive manufacturing, and marine transportation.

But as the new international study noted, its engineering applications have been severely restricted due to the need for high-content expensive alloying elements like Nickel (Ni), Cobalt (Co), or Molybdenum (Mo), and complex heat treatment, while showing poor corrosion resistance.

Machine learning offers a way through this constraint. Back in 2020, scientists from the U.S. Air Force and Texas A&M University demonstrated the potential of 3D printing ultra-strong steel³ using a laser to melt steel powder into place. They used the Eagar-Tsai model to optimize laser settings and reduce printing flaws. The printed samples exhibited tensile strengths of up to 1.4 GPa, the highest reported to date for any 3D-printed alloy, showing that process optimization alone can significantly enhance material performance.

Optimizing high-performance steel compositions and processing parameters using ML employs various modeling approaches, such as the composition-processing-properties (CPP) model. The CPP-ML model, however, imposes high demands on dataset quality, which the CPIP-ML model mitigates by incorporating intermediate variables derived from physical metallurgy (PM) models, CALPHAD, and physicochemical feature (PF) screening.

As the latest study pointed out, the multi-component complexity of UHSDS poses challenges for both PM-guided ML and CALPHAD-combined ML optimization. So the researchers from the University of South China and Purdue University turned to the PF-ML strategy to develop UHSDS cost-effectively.

3D Printing a Super-Strong Steel That Never Rusts

Published in the International Journal of Extreme Manufacturing⁴, the researchers have built an “interpretable machine learning” model specifically to work through 81 physicochemical characteristics of the elements.

Instead of having the AI guess combinations, the team had it analyze specific features such as atomic radius and electron behavior to create an alloy that is ultra-strong, rust-proof, and 3D-printable.

The material was actually developed specifically for the 3D printing process by having the model also analyze how the alloy would react to it.

“This strategy has dramatically accelerated the discovery process and enabled the introduction of a low-cost, short-process strategy for additively manufacturing UHSDS with exceptional corrosion resistance, thereby overcoming critical limitations in current additively manufactured steels,” wrote the study authors.

To create an ultra-high-strength and ductile steel (UHSDS), the team began by screening features to identify which key features affect the material’s ultimate tensile strength (UTS), yield strength (YS), and elongation (EL).

Then they used the interpretable Shapley additive explanation (SHAP) algorithm based on game theory to identify the explicit rules governing the effects of elements on these properties. Next, the evaluation criteria and analysis results were combined to identify alloying elements that can improve both strength and ductility.

At last, the team used NSGA-III (Non-dominated Sorting Genetic Algorithm) to optimize the element content and heat treatment parameters. A novel low-cost UHSDS with a simple single-step tempering treatment was subsequently designed.

Through its study, the team has developed a new strategy for additively manufacturing UHSDS using the PF-ML methodology, while reducing costs, simplifying the process, and improving performance.

The metal produced by the algorithm is Fe-15Cr-3.2Ni-0.8Mn-0.6Cu-0.56Si-0.4Al-0.16C. This mixture of iron and chromium, blended precisely with small amounts of cheaper elements like copper, silicon, and aluminum, was calculated by the algorithm to form the ideal internal structure.

The metal was 3D-printed using a laser-directed energy deposition (LDED) technique, then baked in a short, single-step, six-hour heat treatment (at 480°C), and showed promising results, superior to those reported for additively manufactured UHSDS.

Its mechanical properties displayed, UTS: (1,713 ± 17) MPa, YS: (1,502 ± 33) MPa, and EL: (15.5 ± 0.7)%. This means the newly designed material can withstand about 1,713 Megapascals (MPa), according to the AI model. This performance represents about a 30% increase in the metal strength compared to its raw printed state.

It can also stretch by more than 15% before breaking, representing double the ductility.

Testing the alloy using laser powder bed fusion (LPBF) printers showed that AI predictions are accurate and matched exactly with physical experimentation.

When examining the metal’s internal structure to understand the mechanics behind its performance, the team found that the short heat treatment created nickel-aluminum and copper nanoparticles that blocked structural defects from spreading.

What happens is that when physical stress is applied to the metal, these particles act as roadblocks, which significantly increases the force required to break it. At the same time, tiny pockets of a softer phase function as shock absorbers, which prevent it from breaking under tension.

Furthermore, the material exhibits excellent corrosion resistance, with a corrosion rate of 0.105 mm·a−1 in salt water.

Given that the new alloy degrades by only 0.105 millimeters per year, outperforming many standard commercial stainless steels, the material has potential for much wider applications, especially in the marine and aerospace sectors, where materials often interact directly with moisture.

The authors believe that the PF-ML design strategy is an economical way to advance additive metal manufacturing and can help create strong, custom-designed, rust-resistant metals with speed.

“This work will be of great significance to provide new insights into the development of low-cost and process-simplified UHSDS, especially for the laser fabrication of high-value-added steel components with excellent comprehensive performance,” stated the study.

Investing in Steel Innovatio

While researchers are perfecting these alloys in the lab, commercial leaders like Carpenter Technology are already scaling the infrastructure to bring high-performance 3D-printed powders to market.

In the realm of advanced steel alloys, Carpenter Technology Corporation (CRE ) stands out as one of the strongest companies for developing specialty stainless steels, high-performance alloys, titanium, and nickel-based alloys. The company develops powdered alloys specifically used in 3D additive manufacturing, including standard and custom powders, as well as hardware for powder management.

These products serve the aerospace, defense, medical devices, and energy sectors, where ultra-high-strength, corrosion-resistant 3D-printed steels are most valuable.

The company operates through the Specialty Alloys Operations (SAO) and Performance Engineered Products (PEP) segments.

If we look at Carpenter Technology’s stock performance, it has been enjoying a massive uptrend over the last six years. Late in 2020, CRS was trading under $20, and by mid-2024, the stock price had surpassed $100. But this rally didn’t stop there; the stock price continued its ascension, reaching an all-time high (ATH) of $459 this week.

This sharp re-pricing was driven primarily by the company’s transformation from a traditional commodity steel producer into a high-margin specialty alloys business, with its SAO segment becoming the main profit engine, driven by performance in the aerospace sector.

As of writing, CRS is trading at $423.91, up 34.64% YTD and 122.26% in the past year. This puts the company’s market cap at $21.115 billion. It has an EPS (TTM) of 8.60 and a P/E (TTM) of 49.26. The company’s dividend yield is 0.19%.

Carpenter Technology reported a 31% YoY increase in operating income to $155.2 million for Q2 2026, ending December 31, 2025.

Expectations in the SAO segment “exceeded” with operating income surging by 29% YoY to $174.6 million, “its best quarter on record,” and delivered an adjusted operating margin of 33.1%. Notably, it recorded a 23% increase in bookings for commercial aerospace, while negotiations were completed on multiple long-term agreements.

“The quarterly performance was driven by the SAO segment, which continued to expand adjusted operating margins. Demand in our Aerospace and Defense end-use market continues to accelerate as customers gain confidence with the ramping build rates.”

– Chairman and CEO Tony R. Thene

For the quarter, the company’s earnings per diluted share were $2.09, and adjusted earnings per diluted share were $2.33. Net sales for 2Q26 were $728 million. Cash generated from operating activities, meanwhile, was $132.2 million, reflecting higher earnings and improvements in working capital, which helped adjusted free cash flow reach $85.9 million.

With this strong balance sheet and meaningful adjusted free cash flow, the company is taking a balanced approach to capital allocation, which means sustaining the current asset base and investing in high-value growth initiatives like the $400 million brownfield capacity expansion, which will add melt capacity to the company’s downstream finishing assets and boost long-term growth.

At the end of the quarter, the company had $730.9 million in total liquidity, which comprised $231.9 million in cash and $498.9 million in available borrowings.

During this period, Carpenter Technology also spent $32.1 million in share repurchases against a $400.0 million repurchase program.

Carpenter Technology further reported a one-time accounting loss of $15.6 million for paying off its old debt early. The company had senior unsecured notes that were originally supposed to mature in July 2028 and March 2030, but instead of waiting until then, it chose to redeem them early.

The company also released guidance for the current quarter and the fiscal year 2026, expecting between $177 million and $182 million in operating income and a 30-33% increase to $680 million and $700 million, respectively.

Carpenter Technology is “well-positioned for continued growth beyond fiscal year 2027 with strong market demand outlook for our broad portfolio of specialized solutions, increasing productivity, optimizing product mix and pricing actions,” stated the company.

Latest Carpenter Technology Corporation (CRE) Stock News and Developments

Conclusion

For centuries, steel has been made the same way. The methods got cleaner and more efficient over the decades, but the approach stayed largely unchanged. Now AI-driven design and 3D printing are breaking that pattern entirely.

Developing ultra-high-strength steel used to mean costly alloying elements, lengthy heat treatments, and extensive trial-and-error experimentation. But AI-driven alloy design is making it possible to create stronger, more ductile, and more corrosion-resistant steels, specifically optimized for 3D printing, at lower cost.

The newly developed rust-proof super steel demonstrates machine learning’s capability to address long-standing trade-offs among its key properties while simplifying production processes. With a 30% increase in strength, double the ductility, and superior corrosion resistance, this innovation offers major potential for high-value applications.

Click here to learn all about investing in 3d printing stocks.

References

^{1. Kim, S.-H., Kim, H. & Kim, N. J. Brittle intermetallic compound makes ultrastrong low-density steel with large ductility. Nature 518, 77–79 (2015). https://doi.org/10.1038/nature14144
2. Li, K., Zhang, Y., Wang, X., Liu, H., Chen, J. & Murr, L. E. Additive manufacturing of ultra-high strength steels: A review. Journal of Alloys and Compounds 2023. https://doi.org/10.1016/j.jallcom.2023.17269
3. Tang, M., Pistorius, P. C. & Beuth, J. L. Prediction of lack-of-fusion porosity for powder bed fusion. Scripta Materialia 161, 69–72 (2019). https://doi.org/10.1016/j.scriptamat.2018.10.024
4. Luo, Y., Zhu, T., Pan, C., Ben, X., An, X., Wang, X. & Zhu, H. Interpretable machine learning integrated with physicochemical feature for developing additively manufactured ultra-high strength and ductility steel. International Journal of Extreme Manufacturing 8 (2026). https://doi.org/10.1088/2631-7990/ae5006}