Formation of amorphous alloys by the mechanical alloying of crystalline powders of pure metals and powders of intermetallics
Amorphous powders of Ni/sub 32/Ti/sub 68/ and of Ni/sub 45/Nb/sub 55/ were synthesized by mechanical alloying (MA) starting from either a mixture of pure metal powders (in the appropriate molar ratio) or from powders of the crystalline intermetallics NiTi/sub 2/ and Ni/sub 45/Nb/sub 55/, respectively. For both alloys, the peak temperature increase (above the average processing temperature)= in the powder particles trapped between colliding balls is estimated at 38 K. Thus, the amorphization is attributed to a process other than the formation of local melts followed by the rapid solidification of these melts into the amorphous phase. The amorphization by MA starting from a mixture of pure crystalline powders is attributed to a solid state interdiffusion reaction, the kinetics of which is controlled by the excess point and lattice defects generated by plastic deformation. The amorphization by MA starting from powders of crystalline intermetallics is attributed to the accumulation of point and lattice defects which raise the free energy of the faulted intermetallic above that of the amorphous alloy.
- Research Organization:
- Center for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
- OSTI ID:
- 5535791
- Journal Information:
- Appl. Phys. Lett.; (United States), Journal Name: Appl. Phys. Lett.; (United States) Vol. 49:3; ISSN APPLA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360101* -- Metals & Alloys-- Preparation & Fabrication
ALLOYS
AMORPHOUS STATE
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DIFFUSION
ELEMENTS
INTERMETALLIC COMPOUNDS
METALLIC GLASSES
METALLURGY
METALS
NICKEL
NICKEL ALLOYS
NIOBIUM ALLOYS
NIOBIUM BASE ALLOYS
PHASE TRANSFORMATIONS
POWDER METALLURGY
SYNTHESIS
TITANIUM
TITANIUM ALLOYS
TITANIUM BASE ALLOYS
TRANSITION ELEMENTS