Zh. A. Sentyurina

Fabrication of cast electrodes from nanomodified nickel aluminide-based high-boron alloy to fabricate spherical powders using the plasma rotating electrode process

A complex manufacturing method of billets from material based on high-boron nickel aluminide is proposed. The method includes manufacturing the semifinished alloy products using a combined method of self-propagating high-temperature synthesis and centrifugal casting from oxide feedstock and subsequent vacuum induction remelting with the introduction of Al-based foundry alloys containing nanosized ZrO2 and modifying the structure. The evolution of the microstructure and phase composition is investigated at all production stages. A cast ZrO2-modified cylindrical billet, which possess high purity in regards to gas impurities (O 0.005 wt % and N 0.0001 wt %) and is suitable for the further production of powders by the plasma rotating electrode process, is fabricated according to the proposed technology.

Production of a sintered alloy based on the TiAl intermetallic compound: Part 2. Investigation into forming and sintering processes

A complex production technology of electrodes from the powder alloy based on titanium aluminide TiAl, which includes the stages of fabrication of the powder alloy by calcium hydride reduction, treatment of the powder in a ball hard alloy mill with the addition of Y2O3 as a structural modifier, and the hydrostatic formation and sintering of a billet, is proposed. Formation and sintering processes are investigated for experimental samples and the alloy microstructure is investigated at all stages of process flowchart. The electrode for the plasma centrifugal spraying of the granules is fabricated using this technology.

NiAl-based electrodes by combined use of centrifugal SHS and induction remelting

NiAl-based electrodes of a required size were fabricated by combined use of centrifugal SHS casting and induction remelting in an inert atmosphere and characterized by modern analytical methods. Thus produced electrode materials exhibiting high chemical purity and low content of impurity gases (0.005 wt % O, 0.0001 wt % N) can be recommended for use in centrifugal plasma sputtering of micro granules via the plasma rotating electrode process (PREP).

Production of a sintered alloy based on the TiAl intermetallic compound. Part 1: Calcium-hydride fabrication technology of the Ti–47Al–2Nb–2Cr powder alloy and its properties

Alloy powder of the Ti–47Al–2Nb–2Cr composition (at %) with a structure of TiAl (60 wt %) and Ti3Al (40 wt %) is prepared by the calcium-hydride method. The mode of calcium-hydride synthesis is optimized for the Ti–50Al (at %) model alloy. It is established that the reduction temperature should be no lower than 1100°C, while the excess of the CaH2 reducing agent should be no lower than 15 wt %. The main physicochemical and manufacturing properties of the synthesized Ti–47Al–2Nb–2Cr powder alloy, which provide the formation of dense compact items during its subsequent consolidation processes, are determined using modern analytical methods.

Centrifugal SHS of cast Ti–Al–Nb–Cr alloys

The technique of centrifugal SHS was used to fabricate an alloy with a composition close that of commercially available alloy 48Ti–48Al–2Nb–2Cr by using Ti–Al–Nb2O5–Cr2O3–CaO2 thermite mixtures. The synthesized alloy exhibited a uniform structure and a composition close to that of commercial prototype. Its main drawback is the presence of undesired admixtures of O, N, P, Ca, C, and Si. Further efforts should be oriented on diminishing a contamination level.

Thermal treatment of steel-TiC composite materials produced by laser surfacing

The effect of heat treatment (ageing) on the microstructure and properties of SPN14A7M5/TiC materials produced by laser surfacing is studied. The optimum ageing conditions are found.

Investigation into laser cladding of steel-titanium carbide powder mixtures on a steel substrate

The influence of the main parameters of laser cladding (the laser radiation power, the scanning speed of the laser beam over the treated surface, the consumption of the cladding material (steel SPN14A7M5-titanium carbide (0–20 vol % TiC)), and titanium carbide content in the powder mixture) on geometric sizes (the height, width, and melting depth of the substrate) of the cladded single layer (bead) has been considered. The structure of the cladded material is investigated using optical and scanning electron microscopes, and the hardness distribution from the substrate to the cladded layer is determined.