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In-situ ductile metal/bulk metallic glass matrix composites formed by chemical partitioning

United States Patent

March 23, 2004
View the Complete Patent at the US Patent & Trademark Office
A composite metal object comprises ductile crystalline metal particles in an amorphous metal matrix. An alloy is heated above its liquidus temperature. Upon cooling from the high temperature melt, the alloy chemically partitions, forming dendrites in the melt. Upon cooling the remaining liquid below the glass transition temperature it freezes to the amorphous state, producing a two-phase microstructure containing crystalline particles in an amorphous metal matrix. The ductile metal particles have a size in the range of from 0.1 to 15 micrometers and spacing in the range of from 0.1 to 20 micrometers. Preferably, the particle size is in the range of from 0.5 to 8 micrometers and spacing is in the range of from 1 to 10 micrometers. The volume proportion of particles is in the range of from 5 to 50% and preferably 15 to 35%. Differential cooling can produce oriented dendrites of ductile metal phase in an amorphous matrix. Examples are given in the Zr--Ti--Cu--Ni--Be alloy bulk glass forming system with added niobium.
Kim; Choong Paul (Northridge, CA), Hays; Charles C. (Pasadena, CA), Johnson; William L. (Pasadena, CA)
California Institute of Technology (Pasadena, CA)
09/ 890,480
April 2, 2002
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT The U.S. Government has certain rights in this invention pursuant to Grant No. DE-FG03-89ER452 421 awarded by the Department of Energy, and Grant No. 5F 4920-97-1-0323 awarded by the Air Force Office of Scientific Research.