Material Innovations
DuPont's nontraditional automotive materials
 From left to right: Molded-in-color speed shape featuring DuPont Surlyn; leather featuring DuPont Lycra for increased flexibility; and the mineral/marbled/pale stone look of interior trim and knob featuring DuPont Corian. |
DuPont Automotive is showing the automotive industry that nontraditional materials make for interesting interior accents and exterior finishes. Via the "Vision" series, DuPont is using hands-on displays to show how existing and experimental materials can be adopted as automotive applications.
The supplier's Surlyn offering is used today as a golf ball covering and perfume container, but the tough product is being suggested for other applications. "We expect to use it for such things as door handles and other interior trim. It's of interest because you can get a glossy finish without painting because it's molded-in-color," explained Larry Cole, Executive Product Planning Manager for Interior Systems at DuPont Automotive in Troy, MI.
Many of today's kitchen and bathroom countertops are made of Corian, but the durable material could become an interior trim accent. "It's great for touch points, and you can get a variety of mineral-type looks," Cole said.
So-called stretch and recovery leather is another innovative alternative. Unlike a typical leather hide that is about 2.0-mm (0.08-in) thick, stretch and recovery leather is sliced along its length to produce a 0.2-mm (0.008-in) thickness. The thinner leather is then combined with DuPont Lycra to obtain its stretch and recovery properties. In its first automotive showing, the material is being used on the steering wheel and gear knob of a Saturn concept vehicle.
Holographic flakes (produced, in loose terms, by taking a hologram, grinding the film into small flakes, and then putting the flakes in paint) emit colors from the original hologram when the paint is exposed to natural or artificial light. "It's still in the developmental stage, but it has been used on some concept cars as an exterior paint," said Bob Daily, Color Marketing Manager for DuPont Performance Coatings.
"Vision" concepts illustrate a range of ideas that go beyond conventional materials and textures. "Designers are always looking for something new," Cole said.
- Kami Buchholz
Ames Lab studies processing methods
Most materials scientists follow tried-and-true methods for melting, cooling, and shaping various materials into usable forms even though the science behind those methods is not always fully understood. An effort is underway at the Materials Preparation Center (MPC), part of the U.S. Department of Energy's (DOE) Ames Laboratory, to delve more deeply into the mysteries of processing science—the methods by which metals, alloys, polymers, and ceramics are synthesized to give them specific properties. Ames Lab scientists hope to better understand existing processing methods and develop techniques for making advanced materials for future technologies.
A new program called the Process Science Initiative (PSI) offers a limited pool of competitive funding for two types of materials-processing projects: those that lead to an improved fundamental understanding of existing processing techniques and those that explore new techniques for producing novel materials. The DOE provides funds for the PSI program; MPC and Ames Lab provide the research facilities. The MPC is a designated DOE national user facility that specializes in preparing small samples of high-purity, novel materials that are not available from commercial sources.
It is critical that scientists understand what happens to a material when it goes from a liquid to a solid state because most metals and alloys are made of tiny crystals. The way in which the liquid crystallizes to form the microstructure of the solid determines the material's properties, such as its strength and formability. Subsequent secondary processing, such as rolling or extruding, also affects a material's properties.
"In a lot of the recent research, we've focused heavily on the properties of materials without really understanding how we arrived at, or control, the microstructure," said Brian Gleeson, Assistant Professor of Materials Science and Engineering at Iowa State University and PSI Program Manager. "Materials scientists see the need for research that will give them this type of information."
Larry Jones, Director of the MPC, said determining how to synthesize metals and alloys is a difficult task. "The materials we're dealing with today often have high melting points, or they may easily pick up impurities from the crucibles we melt them in," he said. "And they may need to be cooled in a very regimented way to produce the desired microstructure."
With most complex materials, scientists have a limited understanding of what happens to the metal or alloy while it's being processed. "You have to know the conditions—such as the temperatures, forces, and amount of deformation—affecting that material during processing," Jones said. "Accurately measuring those parameters is not easy when you're dealing with temperatures of 1800°C (3272°F), which is an aggressive thermal environment."
The PSI program is the only known initiative to focus specifically on improving the science of materials processing, according to Gleeson. In fiscal year 2000, four projects received $141,000 in PSI funds. The DOE authorized an increase of the PSI budget to $250,000 for the current fiscal year, which began October 1. Four projects have already been selected to share approximately $175,000 of those funds, with the remaining $75,000 to be allocated later in the year.
Among the projects receiving PSI funds is one in which Ames Lab scientists are studying the properties of liquid/solid interfaces. "In alloy systems, there's a range of solidification where the liquid and solid phases of the material coexist," Gleeson said. "It's the coexistence of the solid and the liquid that really sets the stage for the final product."
The scientists built a rig that enables them to reach and maintain the liquid/solid coexistence and then measure the properties of the interface between the two phases. "This is very fundamental knowledge that could be applicable to a range of other alloy systems," Gleeson said.
Another project that received funding for the current year involves synthesizing and characterizing polymer gels that respond to pH or temperature changes. The goal is to develop polymer gels that would either swell or contract in response to specific pH or temperature changes. "This is a formidable materials-synthesis challenge, but success would be of both fundamental and practical significance," he said.
- Jean L. Broge
