NIST Develops Laser Stirring Method for Metal Additive Manufacturing, Enabling Production of High-Performance High-Entropy Alloys

NIST USA

Overview

Researchers at the U.S. National Institute of Standards and Technology (NIST) have developed a laser stirring method for metal additive manufacturing (AM), enabling uniform mixing of multiple metal elements. This technique facilitates the production of complex alloys, such as high-entropy alloys (HEAs), which were previously difficult to manufacture. The software-based approach is expected to be implementable on existing PBF-LB AM machines, accelerating the development of high-performance HEAs for aerospace and nuclear systems and significantly impacting industry.

In Depth

Key Findings

Researchers at the U.S. National Institute of Standards and Technology (NIST) have developed a novel laser-based technique, termed ‘laser stirring,’ to actively mix molten metals during the metal additive manufacturing (AM) process. This breakthrough enables the production of complex alloys, particularly high-entropy alloys (HEAs), which have historically been challenging to fabricate. This innovation addresses a long-standing hurdle in the development and manufacturing of high-performance materials.

Technical / Clinical Details

In conventional metal AM techniques, especially powder bed fusion – laser beam (PBF-LB), achieving a uniform mixture of multiple metallic elements has been a persistent challenge. This is due to variations in melting points and thermal conductivities of different metals, which can lead to elemental segregation within the melt pool and inconsistencies in the final material properties. NIST’s newly developed laser stirring method precisely controls the laser’s scanning pattern, power, and speed to generate convection currents within the melt pool, ensuring a homogeneous, atomic-level mixing of metal elements. This software-based approach holds the potential for relatively easy implementation on existing PBF-LB AM machines, making it broadly applicable across various industries. Uniform mixing is particularly critical for HEAs, which contain multiple principal elements in near-equiatomic proportions, to ensure their stability and desired performance.

Background & Context

High-entropy alloys are gaining attention as next-generation materials for extremely demanding sectors such as aerospace propulsion systems, nuclear energy systems, and defense, owing to their superior mechanical properties, high-temperature resistance, and corrosion resistance. However, the complexity of their manufacturing has been a significant barrier to their practical implementation. NIST’s technology resolves one of the major bottlenecks in HEA manufacturing—the uniformity issue—paving the way for more efficient and reliable production of these advanced alloys. This development opens new possibilities for designing and manufacturing high-performance components and strengthens the competitiveness of advanced manufacturing in the United States.

Strategic Significance & Outlook

This laser stirring method is expected to accelerate the development and mass production of high-performance HEAs, significantly improving the performance, durability, and safety of components in aerospace and nuclear fields. It will be particularly beneficial for manufacturing parts that must maintain strength under extreme conditions, such as jet engine blades and nuclear reactor structural components. The NIST research team aims to further optimize this technology and expand its applicability to different alloy systems. In the future, combined with AI and machine learning, it has the potential to contribute to the realization of ‘materials foundries’ that autonomously optimize the design and manufacturing processes of even more complex alloys.