Jun 14 2007
Sandia National Laboratories is pioneering the future of superalloy materials by advancing the science behind how those superalloys are made.
As part of Sandia's nanoscale research, a group of experts specializing in inorganic synthesis and characterization, modeling, and radiation science have designed a radical system of experiments to study the science of creating metal and alloy nanoparticles.
This research has vast implications, says Tina Nenoff, project lead. The lightweight, corrosion-resistant materials that the team is creating are needed for weapons casings, gas turbine engines, satellites, aircraft, and power plants.
"What we're doing is taking a completely new approach to thinking about producing superalloy materials," Nenoff says. "We're using radiation to break down the molecular structure of substances and form nanoparticles - a synthetic approach that is flexible and versatile for making large quantities of superalloy nanoparticle compositions that can't be easily created otherwise."
A quick trip down memory lane to the days of high school science class will recall those chapters on material and chemical science defining alloys as a combination of two or more elements, at least one of which is a metal, where the resulting material has metallic properties different - sometimes significantly different - from the properties of its components. For instance, steel is stronger than iron, its primary component.
Superalloys, as the name would imply, stand out from the general population of alloys in the same way Superman would be considered extraordinary compared to the rest of us. These specialized alloys are exceptionally strong, lightweight, and able to withstand extremes that would destroy everyday metals like steel and aluminum.
"These high-performance superalloys are revered for their remarkable mechanical strength and their resistance to corrosion, oxidation, and deformation at high temperatures," says Jason Jones, Sandia researcher.
In the past, the development of these superalloys has depended on chemical and technological innovations, and been driven mainly by the aerospace and power industries where superalloys are in high demand.
"The method of radiation we're studying - known as radiolysis - introduces an entirely new area of research into creating alloys and superalloys through nanoparticle synthesis," Nenoff says. "This process holds promise as a universal method of nanoparticle formation. By developing our understanding of the basic material science behind these nanoparticle formations, we'll then be able to expand our research into other aspects of superalloys, like nickel-based alloys."
Researchers are also translating the results of these experiments into computer simulations. Kevin Leung, Sandia researcher, is leading the effort to use abinitio molecular dynamics, along with other methods, to interpret and understand the controlling factors in the researchers' experiments.
"Using the results from the experiments, together with Sandia's world-class computational capabilities, we?ll simulate the structure of the nanocrystal initiation," Leung says. "By examining the free energy present in the interface between the different materials, we will be able to understand what factors govern the size of these metal alloy nanocrystals. Modeling this region of the metastable phase space right after radiation has been applied promises to be a new and exciting area of research."
"What we're doing is really breaking ground in the fundamental research in the science of the formation of superalloy nanoparticles," Nenoff says. "This is really the new frontier in superalloys."