Disordered Materials
Intense neutron beams offer clues on preparing better surfaces of wear-and corrosion-resistant alloys for use as hip implants.
An ideal crystal is formed from a repeating, three-dimensional pattern of atoms separated by fixed distances. In a disordered material, some atoms can be close together and others can be farther apart than the average distance between atoms. The preferred distances between atoms and the fractions of atoms or molecules separated by various distances can be inferred from neutron scattering. Once the average structure of a disordered material is known, its response at the atomic level to deformation or a temperature change can be determined using neutrons.
Neutrons complement x-rays in studying proteins for information of vital interest to the pharmaceutical, agricultural, and biotechnology industries.
Neutron scattering capabilities at ORNL enable scientists to better understand properties of advanced materials than ever before. These capabilities allow scientists to:
You can hit a golf ball farther with this driver because its head is made of an aluminum-based amorphous alloy whose special features have been evaluated by neutron scattering.
- Understand in situ growth and interface roughening (e.g., in thin magnetized films for pressure sensors and radiation-resistant computer memory devices);
- Obtain detailed information on materials that can be produced only in small quantities or that have a low density of defects (e.g., deformation around lattice defects that contribute to hardening in iron exposed to high doses of radiation)
- Perform time-resolved experiments to study phenomena such as melting and phase transitions (e.g., a change in a metal from magnetic to nonmagnetic or from ductile to brittle)
- Unravel the structure and dynamics of complex multicomponent systems (e.g., sort out the processes for melting down hazardous wastes that best separate out toxic metals and yield commercial products)
- Trace the diffusion of liquids through porous or restrictive media (e.g., find the best process for extracting small amounts of oil from underground sandstone by pumping in steam)
At ORNL, scientists can gathermore detailed information on the microscopic properties of optical fibers for telecommunications, metallic glass (iron-boron) magnets for miniaturized motors and generators, and ion-conducting glasses for possible use in batteries and fuel cells. Also possible arestudies of the long-term stability of contaminated soils and other waste materials encapsulated in glass (which is subject to radiation damage over time).Intense neutron beams are useful for examining the bulk properties and surface preparation of cobaltand titanium alloys for use as medical implants because these alloys are biologically inert and highly resistant to wear and corrosion. In addition, neutronscattering is an important toolfor studying the structure and molecular-level dynamics (e.g.,bonding of silicon atoms) of amorphous semiconductors used in the electronics industry, in which the race to develop new materials is expected to be unusually intense.
