· IngenierÃa ·
G.S. Cho*, K.R. Lee*, K.H. Choe*, K.W. Lee* and A. Ikenaga**
*Advanced Material R/D Center, KITECH, Korea, **Osaka Prefecture University, Japan
67th World Foundry Congress
Combustion synthesis with the advantages of time and energy savings
has been recognized as an attractive alternative to the conventional
methods. In order to improve the surface properties of Al casting
components, Ni-Al intermetallic compounds are fabricated by the
SHS(Self-propagating High temperature Synthesis) process using the
reaction heat of the elemental powders. Three kinds of nickel aluminides,
Ni3Al, NiAl and NiAl3 were produced by the emission heat from the Al
molten metal and a coating layer of intermetallic phase was
simultaneously formed on Al casting alloy surface. Microstructure and
phase formation behavior of Ni-Al based intermetallic compounds
synthesized by combustion reaction were investigated in terms of thermal
and phase analysis using scanning electron microscope(SEM), energy
dispersive x-ray spectrometer (EDS), Electron Probe Micro Analyzer
(EPMA) and X-ray diffractometer(XRD). The microstructures of nickel
aluminides were varied by casting temperature, mixing condition and
mixing ratio of elemental powders. The reaction layer formed between Al
alloy and the powder mixtures of nickel aluminide was observed to be
different depending on process conditions such as green density of
elemental powders, molten metal temperature and chemical composition.
The differences of junction behavior with pouring casting alloys were
compared and the schematic model of bonding reaction was defined.
