MATERIALS - Stir in extrusion tech . . .
Researchers at Oak Ridge National Laboratory have achieved a friction-stir technology milestone by extruding aluminum-based wire in lengths up to 15 feet. Friction-stir, which is also used in welding, is a method that uses the heat from a spinning tool to plasticize metal alloys or composites for reforming, joining or recycling. The ORNL researchers optimized the friction-stir process to extrude the unprecedented long lengths of wire through a die. Along with its energy efficiency benefits through eliminating the need to melt large quantities of metal, the method preserves properties of some solid-phase advanced materials such as oxides or electrical conductors that may otherwise be lost through melting. [Contact: Bill Cabage, (865) 574-4399; cabagewh@ornl.gov]
MATERIALS -- Nanodots to the rescue . . .
By applying the magnetic properties of iron nanodots to complex materials, a research team has overcome an obstacle to getting ultra-thin or highly strained films to perform on par with their bulk counterparts. If the researchers are indeed successful, this work sets the stage for these exotic materials to be used in a wide range of fascinating and potentially technologically revolutionary applications, said Oak Ridge National Laboratory's Zac Ward, lead author of a paper published in Physical Review Letters. The problem lies in the fact that at low dimensions or when the material is under strain it loses the characteristics that make it valuable for use in nano-scale electronics. "What we discovered is a way to activate these materials using the magnetic properties of iron nanodots to control the electron spin and tune the behavior," Ward said. [Contact: Ron Walli, (865) 576-0226; wallira@ornl.gov]
COMPUTING -- Parareal boost for fusion . . .
An application and algorithm tweaked by Oak Ridge National Laboratory researchers to dramatically increase a supercomputer's functionality is providing fusion and climate researchers with the potential to solve problems faster than ever. By using the Integrated Plasma Simulator, a specialized application, combined with Parareal, a mathematical formula that outlines steps to solve a problem, Lee Berry expects researchers to be able to keep pace with the ever-increasing power of supercomputers. "These advances have opened new opportunities to advance our simulation portfolio," said Berry, a member of ORNL's Fusion Energy Division. "For example, discussions are under way to apply this new capability to climate models." [Contact: Ron Walli, (865) 576-0226; wallira@ornl.gov]
MATERIALS -- Details of disorder . . .
Ultrasonic imaging and submarine sonar technologies often rely on materials called ferroelectric relaxors, which are known for their unique electromechanical properties. A study published in Advanced Functional Materials from a team including Oak Ridge National Laboratory has revealed several mechanisms behind the material's behavior. Instead of having one order parameter – which describes how a material transitions between different phases – the relaxors exhibit two order parameters. "This strange effect happens because disorder makes the material more complex. It is very unusual and interesting because classical theories simply do not consider this type of behavior," ORNL co-author Sergei Kalinin said. Researchers say that understanding the materials' underlying mechanisms could help develop and improve relaxor devices for applications in sensing, imaging and energy harvesting. [Contact: Morgan McCorkle, (865) 574-7308; mccorkleml@ornl.gov]
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