Abstract: Electron backscatter diffraction (EBSD) has been developed as a novel technique for
characterizing crystallographic textures in recent years. The present paper proposes an
“in-situ-tracking” approach using SEM and EBSD to examining the microstructural development and
grain boundary variation of stainless steel during elevated 1200 °C service. The results revealed that in
addition to the coarsened grains the fraction of low angle grain boundaries (LABG) became increased
and flattened obviously during service. Comparing to the regular high temperature service (below 900
°C), the present “recovery and recrystallization” process was accelerated due to dislocation fastened
movement and intensive interaction. However, the grain growth mechanism still meet the
well-accepted dislocation model of subgrain combination.
Abstract: Al K ELNES of oxide ceramics, which show reverse spinel and garnet structures
containing two types of Al sites, are investigated site-selectively using TEM-EELS under electron
channeling conditions. We applied a self-modeling curve resolution (SMCR) technique to separate a
set of experimental spectra into individual spectra of individual atomic sites. The refined spectra after
SMCR were in consistent with the theoretical spectra obtained by the first principles electronic
structure calculations. The spectral difference of the six-coordinated aluminum between the two
materials was discussed in terms of the cationic coordination.
Abstract: Pt/AlN multilayered films fabricated by alternative sputtering deposition were
characterized by X-Ray Reflectometry and X-Ray Diffraction. As-deposited films have (111) and
(001) preferred orientation for Pt and AlN, respectively. The X-Ray Reflectivity profiles are
assigned to the total reflection and Bragg reflections due to periodic layer structure. The Bragg
peaks are observed at the 2Theta range beyond 15 degree and the peak intensities increase after
annealing. The reflectivity of the first order Bragg reflection is approximately 65% and is stable
after annealing at 873K. Simulation of the reflectivity profile has shown roughnesses of the Pt/AlN
interfaces are below 0.4nm. X-Ray Diffraction revealed the development of film texture and
formation of superlattice by annealing. The latter indicates periodicity of film is very high.
Abstract: In the present study, pure elemental powders of Fe and S were mixed to give the desired
compositions of Fe50S50. A SPEX 8000D high-energy ball mill was used to synthesize iron sulfide
powders under an Ar-filled atmosphere. The prepared powders were examined by conventional
X-ray diffractometry and synchrotron X-ray absorption spectroscopy. The experimental results
revealed that mechanochemical reactions occurred during the ball milling process for all the
compositions. The Fe50S50 phase was obtained after ball milling for 20 h. Extended X-ray
absorption fine structure (EXAFS) results revealed that the nearest neighbor bond lengths of the
radial distribution function (RDF) for iron decreased when iron sulfides formed. X-ray absorption
near edge structure (XANES) of S K-edges distinguished better the structural evolution of these iron
Abstract: Recently, the study of fine grain steels aimed at achieving into high strength has become
active. Welding is one of the most effective methods for connecting the structural components. For
those cases, the negative influence of any residual tensile stress induced during the welding process
must be considered. It has been proved that shot-peening can effectively solve this problem.
However, the influence of the Shot-Peening process on fine grain steels after welding has only been
briefly reported up to now. In this study, fine grain steels were used, and specimens were obtained
after heat treatment. Residual stress distributions near the surface of the fine grain steel after
shot-peening were measured by X-ray diffraction technology. Moreover, the effect of hardness on
distributions near the shot-peened surface was also estimated.
Abstract: The effect of tempering process on the microstructure of ultra low carbon bainitic (ULCB)
steel produced by relaxation precipitation controlled phase transformation (RPC) has been
investigated by transmission electron microscopy (TEM) and electron backscattered diffraction
(EBSD). The results showed that the final microstructure mainly contained lath-like bainitic ferrite,
granular bainite and martensite-austenite (MA) constituent in ULCB steels. On tempering at 650°C a
slight increase was detected in the effective grain size as the strain-induced precipitates pinned up the
dislocation walls and subgrains. After tempering at 700°C, bainitic ferrite laths started to coarsen and
polygonal ferrite occurred. The effective grain size of ULCB steels in as-rolled condition was 1.5 μm
at the tolerance of 10o~15o measured by EBSD technique.
Abstract: The process of phase transformation in individual Fe-Pt and Fe-Pt-Cu nanoparticles
synthesized by the reverse micelle method with chemical homogeneity and mono-dispersion has
been investigated by in-situ high-resolution electron microscopy (HREM) observation and in-situ
nano-beam diffraction (NBD). The Fe-Pt particles, initially polycrystalline with the chemically
disordered fcc (A1) phase, were reconstructed into A1 single crystals between 550 and 650°C,
followed by a phase transformation from A1 to the chemically ordered fct (L10) phase between 650
and 680°C. The coalescence began almost concurrently with the phase transformation. They
were transformed into round-shaped single-crystalline particles between 680 and 720°C. Similar
processes were also observed in the Fe-Pt-Cu nanoparticles. The temperatures at which these
processes occurred were substantially lower than those required for the Fe-Pt nanoparticles. We
investigated the magnetic-field distribution of a submicron-size island comprising isolated L10
Fe-Pt nanoparticles magnetized along one direction by using in-situ electron holography at elevated
temperatures. Although the magnetization decreased between 212 and 412°C to 25% of the
strength at 25°C, it recovered 67% of the initial strength during cooling. However, when an island
was heated to 512°C, the magnetization diminished and did not recover during cooling. The Curie
temperature (Tc) was determined to be 350°C and was in good agreement with the Tc determined
by bulk measurements, which was approximately 100°C lower than the Tc for bulk Fe55Pt45.
Abstract: The growth and morphology of the intermetallic compounds (IMC) formed at the
interface between the solder ( Sn–3.5Ag–0.5Cu ) and the Cu substrate of the lead - free solder joint
have been investigated by means of isothermal aging at 125°C. The scalloped Cu6Sn5 intermetallic
compound layer was formed at the interface between the solder and Cu substrate upon reflow. The
thickness of Cu6Sn5 layer increased with aging time. Cu3Sn appeared between Cu6Sn5 layer and Cu
substrate when isothermally aged for 100 hours. Compare to Cu6Sn5 , the thickness of Cu3Sn was
rather low, and nearly did not increase with aging time.
In this paper, the comparison was made among the Sn-Pb and the Sn-Ag-Cu(SAC) solders which
were pre-treated differently before soldering.
Abstract: Welding experiences are demonstrated, which were developed on 2205 type duplex and
2509 type superduplex stainless steels (DSS and SDSS). The welded joints were produced by activated
TIG welding and laser beam welding. For the ATIG process, which is a special kind of the
TIG-welding, silica powder was used as activating flux. Microstructural characterizations were applied
for the measurement of ferrite/austenite phase ratio in the weldments. The welded joints were
thermally aged at temperature of 400 °C. The phase transformations produced during thermal ageing
were investigated by optical and scanning electron microscopy and thermoelectric power measurement.
Investigations show that the thermal ageing induced phase transformations are similar at
ATIG-welded weldment and DSS base material, but the incubation time is significantly shorter in
the weldment than in the base material when laser welding is applied.
Abstract: This study investigates the phase compositions in gelcast dense alumina and porous
alumina that were sintered in an inert atmosphere. Both materials were gelcasted using identical slurry
composition except for adding surfactant to slurry intended for porous shaping. The resulting
gelcasted samples were dried and then sintered in argon gas at 1700oC. The X-ray photoelectron
analysis was used for identifying the phase compositions in sintered samples, which was supported
with TG/DTA and electrical measurements. Results showed that, in addition to alumina and carbon
phases, the dense sample yielded Al4C3 and Al, while porous sample yielded aluminum oxycarbides.
The formation of these phases reduced the carbon content through different chemical reactions to a
limited extent because they formed a protective layer on alumina grains, which prevented the direct
contact between alumina and carbon. Subsequent measured electrical resistivities of dense and porous
alumina were, respectively, 0.20 and 0.32 ,-cm, indicating that the carbon networks are preserved in