Abstract: Fe-doped SnO2 nanoparticles have been synthesized by a simple hydrothermal method.
After Fe doping, the as-prepared SnO2 samples were calcined at different temperature from 350-800
°C in air for 1 h. The effects of Fe dopant and calcination on the microstructure and optical properties
are investigated using X-ray diffraction (XRD), High resolution transmission electron microscopy
(HRTEM) , UV-VIS diffuse reflectance spectra (DRS). Results show that the Fe-doped SnO2
crystallites with the rutile phase was directly synthesized during hydrothermal process without
calcination. A dramatically red shift in the absorbing band edge was observed with the decreasing
crystallite size result from the increasing Fe content.
Abstract: Crystalline approximants structurally related to decagonal quasicrystal in the as-cast and
heat-treated Al75Pd15Fe10 alloys and defect structures in them have been studied by means of
high-resolution electron microscopy (HREM). Structural defects of linear and planar types were
found to exist extensively in the orthorhombic ε16-phase formed in the as-cast Al75Pd15Fe10 alloy. In
contrast with the distribution and configuration of the defects in the as-cast ε16-phase, we found that
high-temperature heat treatment promotes the formation of a kind of regular network of structural
defects in the ε16-phase. This suggests that rearrangements of atom clusters and as well as defects
occurred due to the heat treatment. The relationship between the distribution of atom clusters and the
configuration of defects will be discussed.
Abstract: Many studies have been conducted on mechanical properties in nanocrystalline Ni-W
alloys. However, since these results are obtained in the specimens whose thickness is less than 100
μm and whose homogeneity is not strictly controlled, an inherent potential of the nanocrystalline
Ni-W alloy may be hidden. Therefore, it is necessary to fabricate the bulk Ni-W alloy with
sufficient thickness and homogeneity. In the present study, we develop novel electroforming process
and fabricate the homogeneous nanocrystalline Ni-W alloys. The homogeneities of W-concentration
in micrometer scale are confirmed by the W-concentration profiles obtained by the linear analyses
of the energy dispersed spectroscopy (EDS). The single-phase nanocrystalline bulk Ni-W alloy with
the thickness above 2 mm and minimized W-concentration gradient and fluctuation is featured for
the first time.
Abstract: Pure Al (99%) and pure Fe (99.5%) sheets were mutually stacked and severely deformed up
to equivalent strain of 16 by the accumulative roll bonding (ARB) process in an attempt to achieve
bulk mechanical alloying. The deformation was carried out at RT. The Al/Fe sheets ARB processed
by 1 cycle showed a number of shear bands penetrating the stacked layers. The Fe layers, which were
harder than the Al layers, were subdivided by the shear bands into diamond-shaped regions.
Dissolution of Fe into Al was observed and a supersaturated solid solution was formed in the
specimen ARB processed by 10 cycles. It was also found that local amorphization occurred at
interface regions via formation of Al5Fe2 intermetallic compound.
Abstract: The mechanical properties of the nano-size primary α-Ti phase in Ti55Zr18Ni6Cu7Be14
bulk metallic glass (BMG) have been examined through various annealing temperatures and times.
The yield strength and ductility were changed upon variation of α-Ti volume percent originate from
heating conditions. The strength mechanism and associated heating conditions (heating rate, time
and temperature) are discussed in terms of the microstructural observations and mechanical
Abstract: We indicated synthesization of LCMO by hydrothermal reaction. The results of
transmission electron microscopy revealed that the LCMO particles had wide range in size and
various in shapes. The LCMO particles had a perovskite-type crystal structure with some other
phases. Magnetic property was measured by physical property measurement system. Their
crystallinity and magnetization tended to increased with increasing reaction time.
Abstract: Techniques for joint of materials are developed over 2000 years. The metallic liquid jointing
technique which enables the joint of Ti41.5Cu42.5Ni7.5Hf5Zr2.5Si1 bulk glassy alloy without any
crystallization is very useful to produce large bulk metallic glass. High velocity molten alloy
streams are generated by ejection of alloy liquid through two nozzles at different sites. The jointed
region has nearly the same structure, thermal stability and mechanical properties as those for the
original glassy Ti41.5Cu42.5Ni7.5Hf5Zr2.5Si1 alloy.
Abstract: Y-shaped carbon nanowires as a multi-branched carbon nanostructure have potential
applications in electrical nano-devices. In this paper, we report the synthesis of Y-shaped carbon
nanowires obtained from ethanol flames. These Y-shaped carbon nanowires have different
morphologies from one to another. It is interesting that there are two Y-junctions on individual
carbon nanowires. According to our experimental results, the growth mechanism of Y-shaped carbon
nanowires has been discussed and a possible growth model of these Y-shaped carbon nanowires has
Abstract: Al-Cu-Fe-B quasicrystalline and Mo coatings were obtained on the mild steel and brass
substrates by thermal spraying routes for the purpose of replacement of Mo coatings with
quasicrystalline ones. Quasicrystalline coatings were prepared by air plasma spraying and/or HVOF
(High Velocity Oxygen Fuel) techniques followed by subsequent heat treatment, and Mo coatings,
wire flame spraying. For comparative studies of important properties for industrial application,
mechanical properties, bonding strength, surface energy, and tribological behavior were investigated
based on microstructural characterization. Basic mechanical properties such as hardness, fracture
toughness, and elastic modulus of quasicrystalline coating showed comparable values with those of
Mo coatings. De-bonding tests of coatings deposited onto brass substrate indicated that the bonding
strength of quasicrystalline coatings obtained by HVOF techniques exhibit higher value to Mo
coatings. Non-sticking property analogized from surface energy calculation and friction coefficient of
quasicrystalline coatings also showed better performance during the tests. It is suggested from this
investigation that the quasicrystalline coating can be effectively used as a replacement of the Mo
coating, which has shown a recent steep price rise and problems of accidental existence of minor
environment harmful elements such as Cr6+, Pb, Cd, and Hg.
Abstract: Deformation characteristics and forming limit of ultrafine-grained bulk Al-Mg alloy were
examined with upsetting process. The Al-7.5%Mg alloy produced by cryogenic milling and HIP was
subjected to hot hydrostatic extrusion as a final consolidation in fabricating the ultrafine-grained bulk
material. Upsetting was performed to study their mechanical characteristics in a practical forming
process. The extruded specimen showed that the pores remained in spite of the HIP had been
collapsed and almost eliminated. The effective removal of the distributed pores resulted in significant
increase of formability by preventing early cracking. Metallographic investigations showed that the
size of grain remained below a few hundred nanometer scale in the processes.