The Effect of Electron-pulse Modification of the Surface Layer on the Strength Properties of the Ni[3]Al Intermetallic Compound

In this paper it was shown that pulsed electron irradiation forms in the surface layer of the Ni[3]Al intermetallic compound samples a columnar crystal structure oriented perpendicular to the irradiated surface. The dimensions of the crystals of the columnar structure and the depth of the surface layer modification depend on the power density and the duration of the irradiation pulses - with power density increasing , the dispersion of the columnar structure increases, with increasing duration of irradiation pulses, the depth of the surface layer structure modification increases. Modification of the surface layer structure improves the strength properties of Ni[3]Al intermetallic compound samples

Effects of Inert Nanoparticles of High-Melting-Point Compositions on Grain Structure and Strength of Ni[3]Al Intermetallic Compounds

The paper represents experimental findings both in the area of effects of nanoparticles of inert high-melting-point TiN compounds on a Ni[3]Al intermetallic grain structure creation in the conditions of high temperature synthesis under pressure, and in the area of impact of grain structure modification on intermetallic compounds' strength factor temperature dependence. It was demonstrated that appending a stoichiometric composition of nanosized particles of high-melting-point inert chemical compounds (TiN) initiates a manyfold loss of average size of grain of Ni[3]Al intermetallic compounds, synthesized under pressure, as well as a sufficient intermetallic compounds' strength rise within a wide range of temperatures (up to 1 000 degree C). Electron-microscopic evaluations of a synthesized intermetallic structure with TiN nanoparticles, showed that, during the process of intermetallic polycrystalline structure creation from high temperature synthesis products melts, TiN nanoparticles are mainly spread throughout the boundaries and joints of grain structure, acting as stoppers of grain boundaries migration

Influence of the Thermal-force Effect on the Process of Hightemperature Synthesis of the Ni[3]Al Intermetallic Compound

In this work, the intermetallic compound Ni[3]Al was obtained by high-temperature synthesis under pressure at various values of the preliminary pressure on the initial powder mixture (3Ni+Al). The study of pressure-time and displacement-time diagrams gave a coherent picture of the synthesis passage over time. It was found that an increase of preliminary pressure leads to a decreasing of the powder compacts porosity. In this regard, the smallest displacement of the press plunger after initiating the synthesis reaction in the powder compact was observed at the highest value of the preliminary pressure on the compact. The role of preliminary pressure on the initial powder mixture in the process of the grain structure formation of the Ni[3]Al intermetallic compound synthesized under pressure was determined

Modification of Structure and Strength Properties of Permanent Joints Under Laser Beam Welding with Application of Nanopowder Modifiers

In the paper we present the results of experimental study of specially prepared nanosize metal-ceramic compositions impact upon structure, microhardness and mechanical properties of permanent joints produced by laser-beam welding of steel and titanium alloy plates

Structural state scale-dependent physical characteristics and endurance of cermet composite for cutting metal

A structural-phase state developed on the surface of a TiC/Ni-Cr-Al cermet alloy under superfast heating and cooling produced by pulse electron beam melting has been presented. The effect of the surface's structural state multimodality on the temperature dependencies of thefriction and endurance of the cermet tool in cutting metal has been investigated. The high-energy flux treatment of subsurface layers by electron beam pulses in argon-containing gas discharge plasma serves to improve the endurance of metal cutting tools manifold (by a factor of 6), to reduce the friction via precipitation of secondary 200 nm carbides in binder interlayers. It is possible to improve the cermet tool endurance for cutting metal by a factor of 10-12 by irradiating the cermet in a reactive nitrogen-containing atmosphere with the ensuingprecipitation of nanosize 50 nm AlN particles in the binder interlayers

Impact of High-Temperature, High-Pressure Synthesis Conditions on the Formation of the Grain Structure and Strength Properties of Intermetallic Ni[3]Al

The impact of the preliminary load on 3Ni+Al powder mixture and the impact of the duration of the delay in application of compacting pressure to synthesis product under the conditions of continuous heating of the mixture up to its self-ignition on the grain size and strength properties of the synthesized Ni[3]Al intermetallide material have been studied. The grain structure of the intermetallide synthesized under pressure was studied by means of metallography, transmission electron microscopy and EBSD analysis, with the dependence of ultimate tensile strength on the grain size in the synthesized intermetallide having been investigated at room temperature and at temperatures up to 1000°С. It is shown that an increase in the pressure preliminarily applied to the initial mixture compact results in reduced grain size of the final intermetallide, whereas an increase in pre-compaction time makes the grain size increased. A decrease in the grain size increases the ultimate tensile strength of the intermetallide. The maximum value of the ultimate tensile strength in the observed anomalous temperature dependence of this strength exhibits a shift by 200°С toward higher temperatures, and the ultimate strength of the synthesized intermetallide at 1000°С increases roughly two-fold

Nanostructuring and Physical Properties of Metal-Ceramic Composites With a Different Content the Ceramic Components

A comparative analysis of the microstructure and durability of hard-alloy plates treated with high-energy pulsed electron beam generated from the plasma of argon or xenon in steel cutting was conducted. It is shown that the choice of the plasma gas to generate electron from the cathode plasma-filled setting for pulsed electron-beam irradiation has a significant influence on the formation of structural-phase state in the surface layer and the durability of hard-alloy plates in steel cutting