Bulk Metallic Glasses

Typical strengths and elastic limits for various materials. Metallic glasses are unique.

Metallic glasses with extraordinary magnetic properties, and practical methods for processing these materials, have been developed over the past four decades with support from the Office of Science and predecessor agencies. Pol Duwez at the California Institute of Technology produced the first ribbons of metallic glasses, which had unusual mechanical strength, magnetic behavior, and resistance to wear and corrosion that set them apart from conventional crystalline materials. The processing method involved chilling molten metal at rates in excess of 1,000,000 degrees C per second. Duwez and his student William L. Johnson also discovered other alloys that could be made into metallic glasses for high-efficiency magnets, but expensive processing was required to fabricate forms useful for motors and transformers. During the 1980s, Johnson developed new compositions that could be processed without rapid cooling in bulk or three-dimensional form (bulk forms are more than 20 times thicker than the roughly 40-micrometer ribbons), suitable for casting or possibly molding into complex shapes for precision parts, without the costs or wastes associated with machining. Recently, scientists at Los Alamos National Laboratory produced a bulk ferromagnetic glass with a record-low magnetic energy loss that does not require expensive processing, a form appropriate for energy conversion devices.

Scientific Impact: This research opened up a new area of materials science and technology—for which DOE was the sole U.S. supporter until recently—that offers opportunities for increasing the efficiency of magnets, motors, and transformers. Los Alamos is a world leader in research on bulk ferromagnetic glasses, the only form appropriate for motors and transformers.

Social Impact: These materials are used in products ranging from motor components to golf clubs and also have great potential for military applications. The use of bulk ferromagnetic glasses in energy-conversion devices would reduce costly losses from power-distribution systems and corrosion damage, and the consequent reduced use of energy from fossil sources would reduce the rate of release of carbon dioxide into the atmosphere.

Reference: Masuhr A, Busch R, Johnson WL. "Rheometry and Crystallization of Bulk Metallic Glass Forming Alloys at High Temperatures." ISMANAM 1997 - Materials Science Forum. Barcelona, Spain. Switzerland: Trans Tech Publications, 1998: 779-84.

URL: http://www.its.caltech.edu/~matsci/wlj/Johnson.html http://www.its.caltech.edu/~matsci/wlj/wlj_research.html

Technical Contact: Don Freeburn, Office of Basic Energy Sciences, 301-903-3156

Press Contact: Jeff Sherwood, DOE Office of Public Affairs, 202-586-5806

SC-Funding Office: Office of Basic Energy Sciences