Researchers use subatomic particles to examine and improve 3D-printed superalloys for nuclear, aerospace, automotive, and other industries.

As industries push for stronger materials capable of withstanding extreme conditions, researchers are turning to advanced metal 3D printing and atomic-level analysis to create superalloys designed to endure the harsh environments that future technologies may find themselves in.

Alloys are created by blending two or more metals to achieve enhanced properties like increased strength or corrosion resistance, such as the addition of zinc to exposed metals in streetlights and road signs to reduce corrosion. Similarly, superalloys blend metals to improve certain qualities through careful engineering of their atomic structure in precise quantities.

Unlike standard alloys, superalloys are typically formed through complex processes like directional solidification or controlled heat treatments, which result in a unique crystalline structure. This structure enables them to maintain their strength and stability even at extreme temperatures – often exceeding 1,000 degrees Celsius (1,832 degrees Fahrenheit) – and resist deformation under high stress.

While superalloys have been fabricated long before the advent of additive manufacturing, recent research suggests that 3D printing may be the ideal method for producing these advanced materials.

By building a material layer by layer, it offers the precision needed to create complex geometries and customized components – a process that not only enhances the strength and performance of superalloys but also allows for lightweight designs suited for advanced applications.

In a recent study, researchers at Oak Ridge National Laboratory (ORNL), alongside General Electric and the Edison Welding Institute, explored the potential of superalloys created through laser-based 3D printing.

To understand how these advanced materials could be improved for extreme conditions, scientists used neutron beams to test superalloys such as Inconel 718, a nickel-chromium alloy known for its high strength and corrosion resistance, and René 41, a nickel-based superalloy designed for high-temperature applications.

By analyzing internal stresses formed during the additive manufacturing process, the team aimed to develop methods for enhancing the durability and performance of superalloys in future technologies.

At the Spallation Neutron Source and High Flux Isotope Reactor at ORNL, researchers used neutron diffraction – a technique that scatters neutrons off atomic planes within the material to reveal internal stresses and structural imperfections – to examine the deep internal structure of the superalloys.

With this technique, the team was able to measure the residual stress that forms during the 3D printing process, which can weaken the material or cause it to fail under extreme conditions and is particularly problematic in high-performance applications. However, the study revealed that certain heat treatments can significantly reduce these internal strains, resulting in stronger and more reliable superalloys.

The findings from the neutron studies showed that residual stresses were more influenced by the manufacturing process itself – such as laser dwell time and energy levels – than by the chemical composition of the alloys.

By optimizing these parameters and applying heat treatments, the researchers were able to develop a more efficient process for producing robust superalloys, ultimately reducing manufacturing costs while improving material performance in extreme environments.

To conclude the study, the research team highlighted the potential for these findings to influence not only aerospace and energy systems but also other industries that require materials capable of withstanding extreme conditions, such as automotive and nuclear sectors.

By refining the manufacturing process and improving superalloys' resilience, this research represents a significant step forward in creating next-generation materials that will play a crucial role in future technologies.