Research

Super powered microscope will help crack microstructures

The National Science Foundation has backed researchers at the University of Pittsburgh with more than $500,000, which it will use to build a unique transmission electron microscope to monitor the formation of microstructures in 3D printed metals.

This Dynamic Transmission Electron Microscope (DTEM) will help the scientists monitor the Electron Beam Melting process and show them how the microstructures actually form in real time. It can effectively record nanoscale material transformations, which will allow the team headed up by Dr. Jorg M.K. Wiezorek to study the solidification of aluminium alloys that are commonly used in the EBM processes.

“Predicting microstructure formation during rapid non-equilibrium processing of engineering materials is a fundamental challenge of materials science. Prior to advent of the DTEM we could only simulate these transformations on a computer,” Dr. Wiezorek explained.

“We hope to discover the mechanisms of how alloy microstructures evolve during solidification after laser melting by direct and locally resolved observation. Thermodynamics provides for the limiting constraints for the transformations of the materials, but it cannot a-priori predict the pathways the microstructures take as they transition from the liquid to the final solid state.”

Electron transmission microscope that will help us crack microstructures

 

The study will take years

It’s a three-year plan and Dr. Wiezorek’s team will also study traditional welding and joining processes to compare and contrast them with additive manufacturing. If we can isolate the most effective microstructures for certain conditions then we can set about replicating them by design.

Dr. Wiezorek aims to produce computer models that can predict how the process, temperature and other parameters of the production process will affect the microstructures in the final metal or alloy. This data could then be employed to tailor the production process for metals depending on the required specification.

“We are hoping to unravel details of the kinetic pathways taken from the liquid to the final solid structure,” Dr. Wiezorek said. “This research will help us to refine solidification related manufacturing processes and to identify strategies to optimize how materials perform.”

If we control microstructures, we have real power

Microstructures have massive potential and can help us control the elasticity, weight, tensile and shear strength of a metal. If we can truly master microstructures then we can also fine tune the metal along the length of a print to change its characteristics. Before this, a solid study of microstructures could help to improve the uniformity of 3D printed metals. The current production method means that unmelted powder and pores can provide an inconsistent finish to certain metal alloys.

3D printing gives us the chance to look at metal and alloy production from the ground up and if we can leave traditional molds and casting in the past then we can tailor the metal and create gradient alloys that vary in strength, flexibility, weight and shear strength.

This is the tip of the iceberg, of course, and a number of leading names have predicted that material science will provide the biggest breakthroughs in additive manufacturing in the coming years.

This is the next step in microstructure control

Researchers at Oak Ridge National Laboratory demonstrated the ability to manipulate microstructures back in 2014. But this transmission electron microscope, which was originally developed at the Lawrence Livermore National Laboratory, could help take this research to the next level.

We’re looking forward to seeing the results of this extensive study. Simply taking a closer look at the production process today could help us make better metals tomorrow.

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