University of Pittsburgh Receives $500K Grant to Study Formations of Metal Structures on Nanoscale, Using Specialized LLNL Microscope

Much research being performed today in relation to the 3D printing industry can be so complex it takes a while to wrap our brains around what exactly it is these teams of scientists are doing. And from bioprinting blood vessels to isolating enzymes and converting methane to methanol, it’s one thing to decide on a concept of study—but finding to correct tools to do so often presents another challenge. And while research scientists certainly are not above creating what they need to get the job done, sometimes a little help from their friends makes life a lot easier—and very interesting. First it might take a massive grant to get that help, though!

This was the case as a team from the University of Pittsburgh decided to investigate a complex issue regarding how microstructures are created in metal and alloys upon solidification after laser beam melting. The researchers needed an extremely high-powered microscope to comprehensively study these processes, mainly in relation to 3D printing, welding, and joining.

This follows a growing interest in studying metal 3D printing as well, including a recent case we followed as researchers from the Lawrence Livermore National Laboratory (LLNL) studied porosity issues in that particular technology. While LLNL was in that case examining materials to improve the technology for users, the University of Pittsburgh team wanted to know how materials transform on the nanoscale. To do so, they needed a very unique tool, and only one place was in possession of it: LLNL.

Upon writing a proposal, ‘”In-situ transmission electron microscopy of microstructure formation during laser irradiation induced irreversible transformations in metals and alloys,” the Pittsburgh researchers gained substantial funding. This grant, from the National Science Foundation Division of Materials Research, will allow for educational outreach as well as contributing to the university’s materials science curriculum. Most importantly though, this will allow the team, headed by principal investigator Jörg M.K. Wiezorek, PhD, to use the specialized transmission electron microscope developed at Lawrence Livermore National Laboratory.

Dr. Wiezorek, professor of mechanical engineering and materials, will lead his group in using the dynamic transmission electron microscope (DTEM). What makes this particular tool so unique is that it is able to focus in on materials at the nanoscale, recording changes with ‘nanosecond time-resolution.’

“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.”

Figure created by Ryan Chen at the Technical Information Department at LLNL.

Dr. Wiezorek and his team are committed to the study of advanced materials and materials processing, with recent projects examining:

• Electron density and the nature of bonding in transitional metal based materials.
• Surface modification of structural alloys for enhanced performance by severe plastic deformation and grain-boundary-engineering.
• Rapid irreversible transients, such as solidification, in pulsed laser processed metals and alloys.

In this particular research, because the team is so often forced to rely on other methods of examining such a process, now they will be able to confirm the accuracy of digital models, as well as testing how the process changes when exposed to different temperatures and composition. Dr. Wiezorek and his team hope to offer stronger validation concerning findings on processing, structure and alloy properties following the laser irradiation.

“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.”

Discuss your thoughts on this research project further in the Researching Metal Microstructures forum over at 3DPB.com.