Papers by Keyword: Foils

Abstract: The results of microstructure investigation of eutectic alloys Sn Bi and Sn Pb, obtained at cooling rates of the melt 10^-2 K/s, 1 K/s and 10⁵ K/s are represented. Various cooling rates are achieved by graphite mold casting and by ultra fast quenching from the melt. Microstructure and grain structure are investigated by scanning electron microscopy and the electron backscatter diffraction technique. It has found that the melt cooling rate increasing at rapid quenching leads to microcrystalline structure and to a change of the solidification mechanism. The reasons for the transition from lamellar to the microcrystalline structure are discussed.

Abstract: The multilayered materials with different combinations of Ti, Al and Ti-Al intermetallics were prepared by heat treatment and hot pressing (HP) with elemental foils. The microstructures and phase formation of the obtained samples were detected by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). When the HP is applied under the melt point of aluminum, aluminum is the only diffusive element across the oxide films on the surface of the initial foils; however, some unusual TiAl₃ particles are found in the multilayered structure due to the broken of oxide films; after hot pressing for 4 hours, all the aluminum was consumed; many voids exist at the centerline of TiAl₃ layers, which are mainly caused by Kirkendall effect and the difference of molar volumes between reactants and products; before the aluminum is completely consumed, TiAl₃ is the only product in the solid reaction under the melting temperature of aluminum; however, other Ti-Al intermetallics like Ti₃Al and TiAl are formed in the updated temperature diffusion after aluminum is consumed.