The traditional steps in the fabrication of Malay Keris blades which are preserved in traditional knowledge are explained in consistency with the modern metallurgical engineering. These are forging, quenching, tempering and etching. The material selection process for specific parts of the blade is discussed and correlated to the particular fabrication method used to produce the final properties, which consist of the ductility, hardness and the watermark pattern on the blade. Morphologies of the microstructure are also in agreement with the observed properties in which the central strip of the blades possesses some ductility to facilitate forging whereas the harder edge area is made of steel with higher carbon content
The mechanical properties of hypoeutectic silumins can be improved through chemical modification as well as chemical elements or technological processing. This study presents the results of modification of an Al-9%SiMg alloy with aluminium, boron, and titanium. The experiments were conducted following a factor design 2³ for 3 independent variables. The influence of the analyzed modifiers on the microstructure and mechanical properties of the processed alloy was presented in graphs. The modification of a hypoeutectic Al-9%SiMg alloy improved the alloy's properties. The results of the tests indicate that the mechanical properties of the modified alloy are determined by the components introduced to the alloy.
The X2CrNiMoN22-5-3 duplex stainless steel has an austenitic-ferritic microstructure with an average fraction of each phase of approximately 50%. At the duplex stainless steel the nitrogen serves to significantly improve the corrosion resistance of the alloy also in the welded condition. These steels present the excellent corrosion resistance of austenite steel, and the high mechanical behaviour of ferrite steel. However, the performance presented by duplex stainless steels can be drastically reduced by undesirable phases, such as sigma phase, chi phase, secondary austenite and a lot of chromium-rich and carbides precipitates. In this case an upper temperature limit of 300°C has been placed in the use of X2CrNiMoN22-5-3 steel in the industry mainly due to 475°C embrittlement. The purpose of this work was to ascertain how 60 min isothermal heat treatments at 500°C and corrosion time influence on the relative mass loss, profile roughness parameters and endothermal process by dynamic scanning calorimetry curves of heating measurement from 400 to 600°C of X2CrNiMoN22-5-3 duplex stainless steel. The influence of boiling nitric acid on the steel corrosion resistance was investigated using weight loss and profile roughness parameters.
The microstructure and corrosion resistance of the CrN, Cr₂N layer produced by pulse plasma ion nitriding at a frequency of 10 kHz on the Inconel 740H nickel superalloy were examined. The microstructure of the layers were characterized by light microscope and scanning electron microscopy. The corrosion resistance was examined by the impedance and potentiodynamic methods in a 0.1 M Na₂SO₄ solution and an acidified (pH = 4) 0.1 M NaCl solution at room temperature. The layer obtained, about 4.5 µm thick, contains CrN, Cr₂N phases. It is continuous on the entire cross-section of the sample and adheres well to the substrate. However, in the chloride environment it constitutes an inhomogeneous cathodic coating for corrosion and thereby intensifies pitting corrosion of the material. In chloride-less environment, on the other hand, the layer has no essential effect on the corrosion rate of the Inconel 740H nickel alloy.
The effect of high temperature (up to 1120°C)-high pressure (up to 1.1 GPa) treatment on the resulting defect structure of preannealed (450-725°C, up to 96 hours) Czochralski grown Si crystals was studied by X-ray diffraction. The values of the Debye-Waller static factor and of the root-mean-square atomic displacement due to defects were determined for various Lane reflections. Well-defined development of the cluster like defect structure after high temperature pressurization depending to a substantial extent on the preannealing conditions was observed.
The X-ray acoustic method for determination the structure perfection integral characteristics is suggested for slightly imperfect dislocation-free crystals. The method is suitable for investigation of a crystal disturbed both by localized (microdefects) and by distributed (macrostrains) structure defects. It is based on the analysis of dependence of the distance Δx between two minima, arising in the spatial intensity profile I(x) of the X-ray beam diffracted by acoustically excited crystal, upon ultrasound frequency vs. Using the data Δx(v_{s}) for two selected reflections, we calculated the values of the extinction lengths Λ which enabled us to identify the predominate type of structure disturbances as well as to estimate the static Debye-Waller factors e^{-L} and the period of the main macrodeformation λ_{M} for a sample containing simultaneously microdefects and periodic long range deformations. Such approach was used for studying the structure perfection of Czochralski-grown (Cz) and float-zone (FZ) silicon crystals.
Sensitivity of X-ray integral reflectivity of GaAs single crystal to a degree of structure distortions was established to grow considerably in the Bragg diffraction case when the characteristic AgK_{α_{1}} line is changed for more hard white radiation. In effect, the absorption length essentially exceeds the extinction length what results in enhancement of incoherent scattering. Measurements of X-ray integral reflectivity coordinate dependence by single crystal spectrometer permitted to determine the mean level of crystal lattice distortion as well as the degree of structure homogeneity of a sample with dislocations. The Debye-Waller static factor value was estimated from X-ray integral reflectivity magnitudes for the 800 reflection of white radiation.
In the present work, ZnO/CuO composite nanostructures have been grown on fluorine doped tin oxide coated glass substrate by aqueous chemical growth method. To observe the effect of post growth annealing (500°C, 1 min) on the structural properties of ZnO nanorods scanning electron microscope and X-ray diffraction techniques have been utilized. SEM images of post growth annealed (post growth annealed) sample reveal that the average diameter of ZnO NRs has considerably increased in comparison with as grown sample. Moreover after post growth annealing the ZnO NRs showed more clearly hexagonal wurtzite structure. Beside this the NRs are also uniform and well aligned with a high aspect ratio of ~10. In XRD pattern the strongly intense (002) peak of the post growth annealing sample suggest that the crystal quality of the NRs have also been improved significantly. Since the structural improvement have a significant impact on charge transport properties as well, therefore the effect of post growth annealed has also been investigated by the electrical characterization of ZnO/CuO based heterojunction. The current-voltage measurements of the post growth annealed sample showed improvement in the current in comparison with as grown sample. The impedance study has also confirmed that the post growth annealed has influence on the electrical properties. The presented post growth annealed heterojunction of ZnO/CuO may have space in applications like sensors and oxide based diodes in the devices fabrication.
The focus in this study is on the effect of high energy milling on tricalcium silicate, the main constituent of ordinary Portland cement. Changes in the performance, e.g. hydration heat release, due to milling in a planetary ball mill (Pulverisette 5, Fritsch, Germany) were observed. For comparison, carefully milled tricalcium silicate was produced with the almost exactly same particle size distribution by mortar grinding (KM100, Retsch, Germany). In summary, the results indicate that due to high energy milling the performance of tricalcium silicate can be improved significantly: the hydration heat release is much higher at early hydration time. Also the peak and duration of the dormant period was shifted due to high energy milling. The X-ray diffraction analysis shows that the structure of the material changed in such a way that the amorphous content increases. Further results of surface analysis are shown in this study.
In the paper changes of neutron reflectivity of big (120×70×10 mm^{3}) Cu single crystalline monochromators and CoFe (8%at.) single crystalline, polarising monochromators after cold hammering of the starting plates, are described. An almost three times higher number of reflected neutrons (total reflectivity) and about 20% higher intensity in peak maximum were observed, for Cu plates (measured in reflection from (220) plane)), while the mosaic's spread was about 2 times higher than the one measured for a non-treated plate. In the case of CoFe, 3 mm thick plates, a two times higher number of reflected neutrons and almost 60% higher intensity in peak maximum were observed (measured in transmission - from (200) plane) after hammering, while the mosaic's spread increase was rather small (about 15%).
AlGaAs layers grown by molecular beam epitaxy on GaAs substrates were investigated before and after high hydrostatic pressure (1.2 GPa) at high temperature (770 K) treatment (HP-HT treatment). An influence of HP-HT treatment on the properties of the AlGaAs/GaAs system was studied by lattice parameter measurements using the high resolution diffractometer and by X-ray topography. Observed changes in the lattice parameter of the AlGaAs layers after HP-HT treatment are related to the strain relaxation and explained by the creation of misfit dislocations and other extended defects which are visible on the topographs.
The effect of treatment at up to 1270 K under hydrostatic argon pressure, up to 1.2 GPa, on strain relaxation of AlGaAs layers was investigated by X-ray diffraction and related methods. The 1.5μm thick AlGaAs layers were grown by molecular beam epitaxy method on 001 oriented semi-insulating GaAs substrate at 950 K. An increase in intensity of X-ray diffuse scattering, originating from hydrostatic pressure-induced misfit dislocations, was observed for all treated samples. For the samples treated at 920 K during 1 h under 0.6 GPa, the diffuse scattering was confined to the [110] crystallographic direction perpendicular to the direction of dislocations. For the samples treated at 1.2 GPa at the same temperature and time conditions as for 0.6G Pa, a different behaviour is observed, namely the diffuse scattering extends along all azimuthal directions, indicating that dislocations are created in both [110] and [¯110] directions. The change of strain after the treatment was most pronounced for the samples treated at 1.2 GPa for 1 h at 920 K.
A new approach to structure perfection diagnostics of dislocation-free silicon crystals has been developed using the Bragg case of diffraction. The approach is being based on successive measurements of integral reflectivity and the spatial intensity distribution of reflected beam on the same diffraction planes of a real crystal by means of a single crystal diffractometer.
Carbon-free steels of the type Fe-Co-(Mo,W) have been known for long to attain very high hardness levels through precipitation hardening. However, the classical ingot metallurgy route tended to result in brittle materials. Here it is shown that the powder metallurgy route through mixing of elemental powders, pressing and sintering results in materials with excellent combination of hardness and transverse rupture strength if the processing parameters are adjusted accordingly, in particular sintering and heat treatment being critical stages that should result in chemically homogeneous and fine-grained microstructure. If properly processed, these steel grades offer excellent red hardness since the hardening intermetallic phases are much less sensitive to overaging than the secondary carbides in standard high speed steels.
A new approach to determination of microdefect structure parameters by means of single crystal diffractometer is proposed. The approach is based on the measurements of the integral reflectivity of a sample for two selected X-ray wavelengths providing with the approximations of thin and thick crystal, respectively.
The structural perfection of Czochralski grown silicon crystals annealed at 1580-1620 K under hydrostatic pressure up to 10^{9} Pa was investigated by X-ray diffractometry and topography supplemented by the method of absorption of infrared rays. Such treatment suppresses dissolution of oxygen-related defects. From the static Debye-Waller factor dependence on the reflection order it was concluded that large clusters or dislocation loops are the dominant type of defects for most of the samples.
Structure distortions appearing near the surfaces of crystals irradiated by high energy ions (H, Kr, U) accelerated till energy of several MeV using respectively the accelerator U-120 (Kiev, Ukraine), the heavy ions accelerators (Caen, France and Darmstadt, Germany) were investigated by means of various X-ray diffraction methods (topography and diffractometry). Nonhomogeneous distribution of lattice distortions near the surfaces of irradiated crystals were discovered using these methods in all of the samples. Besides the barrier zones where the accelerated ions stopped, the wide distorted regions situated nearer the surface were found. The fine structure of different zones, their extents as well as the level of static Debye-Waller factor were determined. The depth distribution of this factor was compared with the results obtained by using the edge contrast measurements some years ago. This permitted us to draw conclusions about some relaxation of elastic strains in the interference regions after many years.
A diffractometrical method for quantitative evaluation of structure perfection level in silicon single crystals containing various types of near surface distortions is described. The method is based on the spatial distribution analysis of the reflected intensity in the Bragg case of diffraction. To implement the proposed approach one has to satisfy the condition of the so-called low X-ray absorption because in this case the penetration depth of diffracted radiation exceeds the corresponding value of extinction length. It permits us to obtain a remarkable value of noncoherent reflectivity due to defects placed in deep (on the extension of absorption length) regions of a crystal and therefore, to increase the sensitivity of scattering for low distortions of crystal lattice. Using the method described here the extension of various disturbed layers as well as the level of the static Debye-Waller factor of a crystal can be determined. The effect of surface distortions caused by mechanical treatment and the influence of the following thermal annealing as well as irradiation by high energy protons on the defective structure of the samples were investigated.
In this paper we applied the soft-X-ray radiation for generation of point defects, vacancies, and chemical reactions in quartz (SiO_{2}), taking into account our earlier made similar experiments with crystal silicon and importance of quartz for applications in many fields. In this case only radiative Auger's effects with electrons and electric dipole of atoms transitions can generate metastable vacancies, point defects, and induce chemical reactions. Usually, for point defects generation doses of gamma rays are used. We measured values of the Bragg reflections of X-rays and calculated mean square deviations of atoms in crystal lattice for defining the dynamics of irradiated point defects. We accomplished infrared measurements for establishing of generated chemical reactions, and conductivity measurements were also done.
Determination of the integral characteristics of structural perfection of a real crystal (i.e. Debye-Waller's static factor e^{-L} and coefficient of absorption lids due to diffuse scattering) is especially expedient using the suitably selected wavelengths of the X-ray continuous spectrum by investigation of the thickness I(t), coordinate I(x) as well as amplitude I(W) dependencies of intensities at Lane or Bragg diffraction. Here W is an amplitude of weak ultrasound vibrations excited in a sample for suppression of the Bragg component of reflectivity.
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