In this interview, industry expert Chulyong Sim explores groundbreaking advancements in high entropy alloy development, highlighting new methods that can drastically reduce production time and enhance material performance for aerospace, automotive, and defense applications among others.
What are high entropy alloys and why are they important?
High entropy alloys are materials made up of five or more elements, each within an atomic ratio of 5-35%. They generally form a single-phase crystal structure, or they can be characterized by a nearly equal composition entropy basis with an entropy array greater than 1.6 R at room temperature. Unlike conventional alloys, high entropy alloys do not form intermetallic compounds due to high entropy effects. Instead, the elements form a solid solution, leading to severe lattice distortion. This results in excellent strength, hardness, corrosion resistance, and oxidation resistance. This makes high entropy alloys highly functional materials with broad industrial applications.
What are the challenges in developing high entropy alloys?
Despite their advantages, high entropy alloys are difficult to develop. While industrial demand for high entropy alloys is rising, the conventional methods of creating them are slow, inefficient, and require extensive post-processing. The two main methods are:
- Alloy powder method – This involves atomization, but requires additional post-processing.
- Mixing powder method – This uses a ball milling process but also demands secondary processes like spark plasma sintering or compaction.
Both methods take days or even weeks to create and test new high entropy alloys. The trial-and-error approach is time-consuming and makes it hard to iterate on new material compositions quickly.
How does InssTek’s new methodology improve high entropy alloy development?
We have developed a disruptive technology that dramatically shortens and simplifies the high entropy alloy creation process. Our clogged vibration method (CVM) powder feeding system enables the real-time modification of alloy compositions during direct energy deposition (DED) 3D printing.
Instead of restarting the entire process for every composition change, our system allows adjustments on the fly, reducing the time required from weeks to just a few hours per iteration.
Our CVM powder feeding system consists of six powder feeder blocks that operate individually or together. This allows for:
- Single-material deposition by activating one feeder
- Dual-material deposition by activating two feeders
- Multi-material deposition by simultaneously controlling up to six different powders
We have successfully demonstrated stable powder delivery at 0.03 grams per minute over a continuous seven-hour operation—an industry first.
What a brilliant rapidly alloy maker for metallurgy research ! Make your own Alloys !
Video Credit: InssTek, Inc.
What role does the MX-Lab play in your methodology?
Alongside our CVM system, we developed MX-Lab, a core software tool called Material Designer to streamline high entropy alloy research. This software offers an all-in-one solution for material scientists, allowing them to:
- Design sample geometry and alloy compositions seamlessly
- Generate NC code files for 3D printing with a single click
The MX-Lab and CVM system together enable rapid alloy scanning, meaning we can explore new material properties faster than ever before. Additionally, the MX-Lab has an Auto Z feature, which automatically adjusts the laser focusing distance to maintain precise energy density during material deposition.
Image Credit: InssTek, Inc.
What was the process for testing and validating your high entropy alloy samples?
To validate our high entropy alloy development approach, we employed direct energy deposition additive manufacturing (DED-AM) using our CVM powder feeding system.
We designed a combinatorial alloy map to explore various compositions and developed nine different high entropy alloy specimens for testing. Each sample underwent rigorous analysis using advanced characterization techniques.
Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to confirm element distribution within the samples, ensuring uniformity and stability. X-ray Diffraction (XRD) allowed us to verify that the specimens had successfully formed a face-centered cubic (FCC) single-phase structure, an essential characteristic for maintaining desirable mechanical properties.
We also conducted Differential Scanning Calorimetry (DSC) to measure the solvus temperature of the alloys, which reached an impressive 1202 °C, exceeding the standard temperature range observed in traditional high entropy alloys.
Among the nine specimens produced, one exhibited the most stable gamma-gamma prime phase and demonstrated superior high-temperature properties, making it a strong candidate for further industrial applications.
How efficient is your method compared to traditional approaches?
Our CVM powder feeding system, in combination with the MX-Lab software, significantly enhances the efficiency of high entropy alloy development by reducing production time and material waste.
The entire process of producing a full nine-sample batch was completed in just 4 hours and 20 minutes. This included 60 minutes dedicated to setting up stacking conditions, 20 minutes for modeling and parameter adjustments, and 180 minutes for the direct energy deposition (DED) stacking process of all nine specimens.
In contrast, traditional methods can take weeks to produce and test a single high entropy alloy sample due to the need for repeated iterations and extensive post-processing. By eliminating these inefficiencies, our methodology accelerates research and development and lowers costs by minimizing material usage.
This breakthrough represents a major shift in how high entropy alloys can be designed, tested, and optimized, making it possible to explore a wider range of compositions in a fraction of the time previously required.
What are the main applications driving demand for high entropy alloys?
High entropy alloys are particularly valuable for high-temperature applications, which represent approximately 65.5% of 3D printing use cases. Industries such as aerospace, automotive, defence, and power generation benefit significantly from the superior properties of high entropy alloys.
In aerospace, these materials are used for turbine blades and engine components that require outstanding oxidation resistance at extreme temperatures. In the automotive industry, they are ideal for parts that must endure significant thermal stress and mechanical fatigue, improving both performance and longevity. Defence and power generation applications also rely on high entropy alloys for their exceptional corrosion and heat resistance, making them essential for long-term durability in harsh environments.
One of the most notable applications is in nickel-based superalloys, which contain a reinforced gamma-prime phase that enhances mechanical strength, oxidation resistance, and corrosion resistance even at temperatures exceeding 1000 °C. This ability to withstand extreme conditions makes high entropy alloys indispensable in industries where material performance under stress is critical.
Beyond high entropy alloys, what other material innovations can your technology support?
While our technology has been instrumental in advancing high entropy alloy research, its capabilities extend beyond these materials.
Our system is also well-suited for the development of metal matrix composites (MMCs), which combine metals with ceramic or reinforcing materials to enhance mechanical properties such as strength, wear resistance, and thermal stability.
Our CVM powder feeding system and MX-Lab software enable the fabrication of functionally graded materials (FGMs), which are designed with a gradual variation in composition and properties, making them ideal for aerospace and biomedical applications.
The ability to control multi-material deposition with precision allows researchers and engineers to create custom material compositions tailored to specific industrial needs. By leveraging these advanced capabilities, we are opening up infinite possibilities in material science, accelerating research and commercial applications across multiple fields.
About Chulyong Sim 
Chulyong Sim is currently the Director of AM Technology and has been an AM engineer at InssTek since 2013. Utilizing 3D printers such as MX-Lab and MX-Fab, he has been actively involved in additive manufacturing process development and material research, addressing various challenges in shape fabrication and material studies.
He holds a Master’s degree in Applied Materials from Hanbat National University and continues to expand his expertise in new alloy material research using the MX-Lab 3D printer.
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