A material world: the future of our material world
Professor Simon Ringer, Director of the Australian Centre for Microscopy & Microanalysis (ACMM), uses sophisticated imaging and probing techniques to study the relationships between structure and properties of materials.
“Materials science is the point where science and engineering meet,” says Ringer. “We work on characterising and relating microstructure to properties in two main classes of materials. The first are load bearing materials, where we focus on light metals such as aluminium, magnesium, titanium and advanced steels. These materials are significant economically and environmentally with exciting new opportunities in building and construction, automobiles and aerospace.”
“The second class are functional materials, which exhibit functional characteristics other than mechanical strength, such as being photovoltaic, magnetic or electronic. They are widely used in information and communications technologies.”
Part of Ringer’s program in light metals involves the investigation of the atomic architecture of new alloys. Alloys that are lighter, stronger and more corrosion resistant will contribute much to the current energy issues. For example, lighter cars, trucks and aeroplanes open the pathway to new propulsion systems that use ‘greener’ fuels.
“There are a number of techniques we use to characterise materials, including transmission electron microscopy, X-ray diffraction, scanning electron microscopy and atom probe tomography,” says Ringer. “Our techniques allow us to investigate the nanostructure of new materials, right down to the precise locations and relative proximities of individual atoms. This architecture governs the resultant properties of that material.”
“For example, atom probe tomography is giving us insights to develop design rules for new alloys. In most materials, when you design the structure for high strength, you end up with low ductility and the material will be brittle, and the converse applies. This is a well known conflict in materials property-performance space.”
“However, by analysing the atomic locations of the different metals making up particular alloys, we have found that clusters of certain metal atoms have a major effect on the total strength of the material whilst actually enhancing the ductility. To achieve these results, we have had to develop new computational algorithms which allow us to interrogate the data from the atom probe and identify and isolate the atomic clusters that enhance strength.”
The ACMM at the University of Sydney is also national headquarters of the Australian Microscopy and Microanalysis Research Facility. This organisation is a national grid of laboratories that provide Australian researchers with state-of-the-art instrumentation and expertise to explore the structure and chemistry of materials, be they biological, physical or chemical in nature.
“The images and spectroscopy from the microscopes in our facility allow scientists and engineers to see and understand the inner workings of the nano-world. It is a very exciting time.”