The angles where atoms meet could provide a path to new materials under extreme conditions

How can we design materials that are stronger and lighter? What about new materials for extreme conditions such as jet engines and spacecraft? Associate Professor of Materials Science and Engineering in the PC Rossin College of Engineering and Applied Sciences at Lehigh University The answer, says one Fadi Abdel-Jawad, may lie in the infinitesimal regions, or boundaries, where the atoms in a crystal converge.

Abdel-Jawad and his collaborators at the U.S. Department of Energy’s Center for Integrated Nanotechnology (CINT) are uncovering how these tiny boundaries can profoundly influence the properties of nanomaterials.

“The atoms come together to form nanocrystals, which are essentially structures about 10,000 times smaller than the width of a human hair,” Abdel-Jawad explains. “Think of these crystals coming together like puzzle pieces or like tiles on your kitchen floor. Billions of these nanocrystals stacked on top of each other form most engineering materials. ”

According to the researchers, the regions where the crystals come into contact play a major role in determining the material’s behavior. The team’s research was recently published in Nano Letters.

In this article, “Triple junction segregation governs the stability of nanocrystalline alloys,” we discuss how a small feature in nanomaterials known as triple junctions is important in maintaining the stability of these materials at high temperatures. We are considering whether we can play a role.

gold in the corner

Nanocrystalline materials have extremely fine structures made up of large numbers of small crystals. This small crystal size increases the strength of the material. However, it is difficult to keep these crystals small and stable over long periods of time, as they tend to grow, which can weaken the material.

The researchers in this study discovered that the key to maintaining the high-temperature stability of these materials lies in the triple junctions, the corners where three of these nanocrystals meet. Imagine three puzzle pieces with their corners stuck together.

Scientists have discovered that when certain atoms are added to form an alloy, those atoms preferentially occupy the triple bond positions. This “chemical segregation,” or clumping of atoms at triple points, prevents grain growth and thereby prevents the material from losing strength over time.

This particular study demonstrated that carefully placed gold atoms at the triple points of platinum nanomaterials allow the material to remain stable even under high temperature conditions.

“By understanding this process, scientists will be able to design better nanocrystalline alloys. They will be able to select specific elements that reach the triple junction and stabilize the material. “This is especially important in applications where strength and durability at high temperatures are key,” says Abdel-Jawad. These include the aerospace and energy industries. ”

Harness the power of teamwork

Abdel-Jawad, a computational materials scientist at Lehigh University, conducted a large-scale computational study that predicted these results. To validate the model, the computational team partnered with the Center for Integrated Nanotechnology (CINT). CINT provides advanced tools and expertise for nanoscale research, enabling cutting-edge research in materials science, nanofabrication, and nanophotonics for scientific and technological advances.

“This is a great example of collaborative science,” says Dr. Brad Boyce, senior scientist at CINT and co-author of the study. “Our ideas about how to design new materials by tuning their features at the nanoscale are maturing as a result of our ability to simulate the complex arrangement of atoms that make up these materials.”