Alloy Design and Development Laboratories
The Thoma Research Group

Research

Our research on metal additive manufacturing, or 3D printing, centers on innovative design for multi-functionality in engineering applications, high-throughput experiments for fundamental alloy discovery, and microstructural control for qualification and certification of engineering components.

Metal additive manufacturing, at this time, lends itself to lower volume and higher cost components. Future trends and research will increase the volume and lower the cost in this rapidly growing sector. New discoveries on material properties, metamaterials, and light-weighting are within our reach.

Defect control during processing is an important safety feature for the fabrication process. Our research looks at a variety of methods to promote safety in the additive process.

You can watch a short introduction to the lab’s capabilities and research programs here.

Research Focus Areas

Alloy Design
-High-throughput experimentation and characterization
-High entropy alloys
-Bulk metallic glasses
-Functionally-graded materials
-Controlled solidification
-Phase transformation

Manufacturing Design
-Machine learning for process optimization
-Hierarchical structures
-Multi-material additive manufacturing

EXPLORING REFRACTORY HIGH-ENTROPY ALLOYS  FOR HIGH-TEMPERATURE ENERGY APPLICATIONS

Refractory high-entropy alloys (RHEAs) offer exceptional strength at elevated temperatures, making them promising for advanced energy applications such as nuclear fusion first-wall materials. Tailoring compositions within RHEA systems and utilizing the high cooling rates of laser powder bed fusion can refine grain structures, enhancing performance. Ongoing research explores coupling high-temperature thermomechanical testing with DFT and CALPHAD methods to develop predictive models for RHEA properties. The broader goal is to design high-performance materials optimized for extreme environments in next-generation energy systems.

UNDERSTANDING MICROSTRUCTURAL RESPONSE

Scientists work on characterizing the microstructure of additively manufactured metals across length scales to determine the influence of processing parameters on structure and mechanical properties. Future research will aim to develop a more complete understanding of how microstructural variations affect mechanical response from the nano to macroscales, with an emphasis on mesoscale characterization and modeling techniques.

 

 

IMPROVING PERFORMANCE OF STRUCTURAL MATERIALS

The Alloy Design and Development Lab is part of the Center for Extreme Events in Structurally Evolving Materials, a multi-university research initiative led by Professor Curt Bronkhorst. The group investigates ductile failure mechanisms in low-carbon steel under high strain rates, focusing on adiabatic shear banding and dynamic recrystallization. By conducting metallographic imaging and analysis, the ADD Lab provides critical insights into microstructural responses to deformation. This research aims to advance the fundamental understanding of material behavior in extreme conditions, contributing to the development of more resilient structural materials.

ACCELERATING MATERIALS DEVELOPMENT TO ADVANCE CLEAN ENERGY PRODUCTION

Dan Thoma and a group of University of Wisconsin-Madison researchers received a $1.8 million grant to develop new materials for multiple uses, including the ability to withstand the corrosive environment within a molten salt nuclear reactor.

3D PRINTING WITH STAINLESS STEEL

Researchers developed Bucky Badger figurines which were 3D printed by selective laser melting (SLM) of a power bed. In this process, support scaffolding is designed to provide consistent heat transfer during build-up. Scaffolding designs are being investigated to reduce material and consumption cost. The effects of process parameters and heat treatment on the microstructure of metal is also being investigated to achieve better control over microstructure evolution throughout the printing process.

ENHANCING DED EFFICIENCY AND EXPANDING PREDICITVE MODELING

Additive manufacturing (AM) enables the design of advanced materials with tailored microstructures for site-specific properties. In Directed Energy Deposition (DED), controlling processing conditions influences material structure and performance. For example, adjusting deposition thickness in 316L stainless steel impacts dendrite arm spacing (2.7–5.1 microns) and hardness (160–219 Vickers). Predictive models help optimize deposition height and powder capture efficiency by balancing key parameters like laser power and mass flow rate. This research aims to enhance DED efficiency and expand predictive modeling to Magnesium and Niobium alloys, contributing to the broader goal of designing high-performance materials for next-generation engineering applications.

ankur's research

USING MACHINE LEARNING TO DEVELOP NEW ALLOYS

The high-throughput fabrication and characterization techniques of additively manufactured metals is an area of emphasis in the ADD Lab. Specifically, the effects of SLM processing parameters will be assessed on the basis of density, microstructures, and performance. Ankur Agrawal aims to develop processing maps and solidification maps for the SLM process using high-throughput techniques. This research is useful for microstructural designing of as-fabricated samples and will improve the performance of additively manufactured components. Ankur also aims to couple his work with modeling and machine learning techniques to understand the fundamentals of laser-powder interaction and to predict the optimal processing conditions for new alloys.

 

DESIGNING NEW MICROSTRUCTURES

Studying the use of metal additive manufacturing (AM) to design novel microstructures in alloys is one aim of our research. With applications in structural materials for extreme environments such as the ones encountered in power plants, this research could lead to big societal impact. Enhanced microstructural control could help scientist develop and discover superior components which are more resistant to degradation. For example, the directed energy deposition AM technique enables us to fabricate functionally-graded components, with different microstructures, and properties, at the surface and in the bulk of the component.

Publications

For the most recent list of publications please visit Dr. Thoma’s Google Scholar profile.

  1.  “Influence of Solidification-Induced Sub-Granular Structures on Radiation-Induced Swelling in an Additively-Manufactured Austenitic Stainless Steel,” G. Meric de Bellefon, et al.  J. of Nuclear Materials, https://www.sciencedirect.com/science/article/pii/S0022311519305343, 523, 291 (Sept. 2019)
  2. “An Investigation into the Challenges of Using Metal Additive Manufacturing for the Production of Patient-Specific Aneurysm Clips,” B.J. Walker, et al., J. of Medical Devices, https://asmedigitalcollection.asme.org/medicaldevices/article/13/3/031009/727256/An-Investigation-Into-the-Challenges-of-Using, 13,3  031009 (Sept. 2019)
  3. “High-Throughput Synthesis of Mo-Nb-Ta-W High-Entropy Alloys via Additive Manufacturing,” M. Moorehead, et al. Materials Design,  https://www.sciencedirect.com/science/article/pii/S0264127519307968, 187 108358 (Feb. 2020).
  4.  “Experimental Validation of Topology Optimized, Additively Manufactured SS316L Components,” B. Rankouhi, et al., Materials Science and Engineering A. https://www.sciencedirect.com/science/article/pii/S0921509320301386, 776,3 139050 (March 2020)
  5. “A Comparison of 316L Stainless Steel Parts Manufactured by Directed Energy Deposition using Gas Atomized and Mechanically Generated Feedstock,” M. Jackson, et al., CIRP Annals Manufacturing Technology, (April 2020).
  6. “Production of Mechanically-Generated 316L Stainless Steel Feedstock and its Performance in Directed Energy Deposition Processing as Compared to Gas-Atomized Powder” M.A. Jackson, A. Kim, Jacob A. Manders, J. D. Morrow, D.J. Thoma, F.E. Pfefferkorn, https://www.sciencedirect.com/science/article/abs/pii/S1755581720300638?via%3Dihub Manufacturing Science and Technology (accepted, 2020).
  7. “High-throughput Experimentation for Microstructural Design in Additively Manufactured 316L Stainless Steel” A. Kumar Agrawal, G. Meric de Bellefon, D.J. Thoma, Materials Science and Engineering https://www.sciencedirect.com/science/article/abs/pii/S092150932030914X, AA793139841 (2020).
  8. Origins of Dislocation Structures in an Additively Manufactured Austenitic Stainless Steel 316L” K.M. Bertsch, B.M. de Bellefon, B. Kuehl, D.J. Thoma Acta Materialia, https://www.sciencedirect.com/science/article/abs/pii/S1359645420305796, 19919-33 (2020).