Microstructural analysis of rapid solidification and undercooling in the Al-Ge system

Journal Article · Sun Jan 01 04:00:00 EST 1984 · Mater. Res. Soc. Symp. Proc.; (United States)

OSTI ID:6736416

Kaufman, M J; Fraser, H L

Submicron powders, amorphous films and melt spun ribbons of various Al-Ge alloys have been analyzed to determine the relative roles of undercooling and cooling rate in the production of non-equilibrium structures. All analyses were performed in transmission electron microscopes equipped with energy dispersive x-ray spectrometers. The submicron powders, produced by electro-hydrodynamic atomization, were analyzed in their as-received condition and then annealed and/or melted using the electron beam as a local heating source. Once molten, the liquid droplets were undercooled at different cooling rates by varying the rate of beam obstruction. In this manner, a number of different microstructures were produced. These included metastable crystalline phases and mixed amorphous/crystalline structures. By combining this technique with a microscope heating stage, it was possible to carry out controlled dynamic undercooling experiments and determine phase selection as a function of undercooling and composition. The amorphous films were rapidly heated with the electron beam in the microscope and metastable as well as stable phases were produced. The results of these complementary analyses will be compared and discussed with reference to current models and theories of rapid solidification. 11 references, 6 figures, 1 table.

• Research Organization: Univ. of Illinois, Urbana
• DOE Contract Number: AC02-76ER01198
• OSTI ID: 6736416
• Journal Information: Mater. Res. Soc. Symp. Proc.; (United States), Journal Name: Mater. Res. Soc. Symp. Proc.; (United States) Vol. 28; ISSN MRSPD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
AMORPHOUS STATE
BEAMS
COOLING
CRYSTAL STRUCTURE
DATA
ELECTRON BEAMS
EXPERIMENTAL DATA
FILMS
GERMANIUM ALLOYS
INFORMATION
LEPTON BEAMS
MICROSTRUCTURE
NUMERICAL DATA
PARTICLE BEAMS
PHASE TRANSFORMATIONS
POWDERS
SOLIDIFICATION
TEMPERATURE DEPENDENCE
TIME DEPENDENCE