MAGNETIC PROPERTIES OF SINGLE CRYSTALS (MnIn2S4)1–х–(AgIn5S8)х SOLID SOLUTIONS

Single crystals of solid solutions (MnIn2S4)1-х–(AgIn5S8)х have been grown with the Bridgeman method in the whole range of temperatures. The crystals structure and composition were determined. The study of the given single crystals in the temperature range 2–300 К and magnetic fields to 10 T was carried out. It is set that the given crystals are paramagnetic in the whole studied range. The specific magnetic moment increases with the temperature.

Development of Nickel Based Superalloys for Advanced Turbine Engines

Superalloys have been developed for specific, dedicated properties and applications. One of the main application for this material is advanced, high-performance aircraft engines elements. Turbine engine creates harsh environments for materials due to the high operating temperature and stress level. Hence, as described in this article, many alloys used in the turbine section of these engines are very complex and highly optimized. This article provides an overview of structural changes that occur during the aging process of wrought and cast alloys and provides insight into the use of precipitated particles to achieve desired structures. Example will focus on alloy Inconel 718 and CMSX-4. Functional properties of these alloys can be achieved by choosing proper heat treatment parameters to obtain required rate between secondary phases. The paper also attempts to determine structural perfection and changes of crystallographic orientation along the axis of growth of single crystal nickel superalloys cast using X-ray topography and Laue diffraction method. Single crystal bars and turbine blades were manufactured in VIM furnace using the Bridgeman method. Withdrawing rates typical for CMSX-4 superalloy were used. It has been found that with increasing withdrawing rate the nature of distribution along the axis of growth of the angle of [001] direction deviation from the axis of single crystal blades growth had changed. The change of the withdrawing rate results also in the rotation of γ’ phase in the form of cubes against the axis of single crystal blades growth.

The Optical Properties and the Structure of CuInS2 Thin Films Deposited by Oblique Angle Deposition Technique

The oblique angle deposition (OAD) technique was used to deposit copper indium disulfide (CuInS2) films onto glass substrates by a vacuum thermal evaporation method. The powder source used in this work was obtained from the crushed CuInS2 polycrystalline ingot grown by Vertical Bridgeman method. In order to study the influences of depositing angle on the optical property and the structure of the CuInS2 films, the depositing angle θ was varied from 10° to 70° with a 30° gradient. These films were characterized by SEM, XRD and UV-Vis spectrophotometer. The results showed that the optical property and the structure of the films were closely related to the depositing angle θ. When the depositing angle θ increased, the band gap increased and the intensity of (112) characteristic peak of the CuInS2 films decreased.

Structural Perfection of a Single Crystal Nickel-Based CMSX-4 Superalloy

The aircraft engines turbine blades are manufactured from nickel-base superalloys and they are often in a single crystal form. This ensures the best high-temperature creep resistance as compared with blades of equiaxial grains microstructure and of columnar grains microstructure. Turbine blades were manufactured in an ALD Vacuum Technologies furnace. The study has examined structural perfection of single crystal blades obtained by Bridgeman method from CMSX-4 nickel superalloy at various withdrawal rates: 1, 2, 3, 4 and 5mm/min.

Sub-Grain Size and Hall-Petch Relation in Pure Copper Single Crystals

The effect of sub-grain on the yield stress of pure copper single crystals with the [253] orientation was investigated by using the etch pit technique. The single crystal plates were successfully prepared from the seed crystals, which were produced at the melting temperature of 1473 K by the Bridgeman method. The present investigation confirmed the Hall-Petch relation concerning the effect of sub-grain boundaries on the macroscopic yielding of pure copper. The result derived from the extrapolation of the relationship of critical resolved shear stress (CRSS) and the initial dislocation density and sub-grain size is in good agreement with the evaluation in high purity copper single crystals of low dislocation density.

Photoacoustic properties of single crystal PbTe(Ni)

Single crystals of PbTe(Ni) were investigated by the photoacoustic method. They were produced using the Bridgeman method. These crystals have a sodium chloride cubic lattice and could be cleaved paralel to the plane orientation (200). They were of the n-type. Phase and amplitude photoacoustic spectra were measured using a transmision detection configuration set-up. Photoacoustic (PA) spectra (single and normalized) were numerically analyzed using the Rosencwaig-Gersho model. Thermal diffusivity and some electron-transport parameters were determined. These results were compared with existing results for pure single crystal PbTe. Thermal difusivity of PbTe(Ni) is a bit higher than the thermal difusivity of pure PbTe. This is the consequence of a decreasing concentration of the majority free carriers in the doped alloy. .