Thermal Stability of Structure and Properties of Gradient and Gradient-Layered Coatings of the Ti–Al–Si–Cu–N System

Russian Physics Journal - Using the methods of dark-field electron microscopy analysis, energy-dispersive X-ray microanalysis, hardness measurements and scratch testing, the variations of elemental...     

Structure and Mechanical Properties of Cu–Al–Si–Mn System-Based Copper Alloy Obtained by Additive Manufacturing

Russian Physics Journal - The paper studies the structure and mechanical properties of the copper alloy based on a Cu–Al–Si–Mn system, produced by wire-feed electron-beam additive...     

Effect of the Energy of Krypton Ions on the Structure and Hardening of Ti–Cr–N Coatings

Russian Physics Journal -     

Composition,Structure, and Mechanical Properties of (Ti–Hf)N Coatings on Titanium Alloy

Technical Physics - Variations of the composition, structure, and mechanical properties (hardness, elastic modulus) of (Ti–Hf)N coatings with increasing Hf content (Ti : Hf ratio) are...     

Modification of the Surface Properties of Free Si–Cu Films by Implantation of Active Metal Ions

Technical Physics - Using the methods of Auger electron spectroscopy, electron energy loss spectroscopy, and UV photoelectron spectroscopy, the influence of Ba+ ion implantation on the...     

Investigation of the Resistance of K-208 Glass with Optically Transparent Al–Si–N Nanocomposite Coatings to High-Speed Microparticle Impact

Russian Physics Journal - Results of studying the structural-phase state and mechanical properties of Al–Si–N coatings fabricated by pulsed magnetron sputtering on a K-208 glass...     

Formation of Ti1–x Si x and Ti1–x Si x N films by magnetron co-sputtering

The paper reports on surface morphology, structure and microhardness of TiSi–N films formed by cosputtering from two target-facing unbalanced magnetrons, equipped with pure Ti and Si targets, on an unheated substrate rotating in front of both targets. The ratio Si/Ti in the TiSi–N film was achieved by modifying the magnitude of currents in the individual magnetrons and by the addition of nitrogen to the film. The rotation of the substrate has a strong effect on the film deposition rate and its morphology. The deposition rate is 3 times lower than that of the film deposited on a stationary substrate. The surface roughness of a polycrystalline Ti film deposited on the rotating substrate is considerably higher than that on a stationary substrate. On the contrary, the surface of an amorphous Si film is smooth and there is no difference between the roughness of Si films sputtered on stationary and on rotating substrates. The hardness of the film increases with increasing Si content and with the addition of nitrogen to the TiSi film. The Ti(26 at.%)Si(8.5 at.%)N(65 at.%)-film sputtered on an unheated rotating steel substrate, held at a floating potential, exhibited the best result with a hardness of 29 GPa.     

Deposition of ultrahard Ti–Si–N coatings by pulsed high-current reactive magnetron sputtering

We report on the results of investigation of properties of ultrahard Ti–Si–N coatings deposited by pulsed high-current magnetron reactive sputtering (discharge pulse voltage is 300–900 V, discharge pulse current is up to 200 A, pulse duration is 10–100 μs, and pulse repetition rate is 20–2000 Hz). It is shown that for a short sputtering pulse (25 μs) and a high discharge current (160 A), the films exhibit high hardness (66 GPa), wear resistance, better adhesion, and a lower sliding friction coefficient. The reason is an enhancement of ion bombardment of the growing coating due to higher plasma density in the substrate region (10¹³ cm^–3) and a manifold increase in the degree of ionization of the plasma with increasing peak discharge current (mainly due to the material being sputtered).     

Structure of the B2 phase in Ti–25Al–25Mo alloy

The structure of the B2 phase has been investigated in Ti–25Al–25Mo alloy using Rietveld refinement of X-ray and neutron diffraction data in as-cast and solution-treated conditions. Different initial structure models have been used for the refinement. The site occupancy of the various chemical constituents in the B2 phase has been calculated and compared with earlier investigations. The relative merits of neutron diffraction over X-ray diffraction for structural refinement of the B2 phase in Ti–25Al–25Mo alloy have been demonstrated.     

Specific Features of the Properties of Co–Cu Granular Media Caused by the Structure of the Material

A comparative analysis of rapidly quenched strips and thin films prepared from Co–Cu alloys with giant reluctance is performed. It is established that their microstructure and phase composition differ strongly. Precipitates of Co-enriched phase of two types that differ in their origin and sizes are present in strips. Large particles (100 nm) having the fcc structure determine the magnetic properties, and small particles ( 5 nm) determine the reluctance. In films, Co particles of only one type are detected. They have hexagonal close-packed lattice, can be in superparamagnetic and ferromagnetic states, and yield the corresponding contributions to the giant reluctance. The above-indicated specific features in the microstructure lead to different magnetic and reluctance properties of strips and films.     

Modeling the crystallization of a Ti–Al nanoparticle by the molecular dynamics method

Crystallization of the Ti–Al intermetallide in the process of cooling from a melt at a constant volume has been simulated numerically using the molecular dynamics method.     

Influence of Thermomechanical Treatment on Structural-Phase Transformations and Mechanical Properties of the Cu–Al–Ni Shape-Memory Alloys

Russian Physics Journal - Using the methods of optical and electron microscopy and electron and X-ray diffraction analyses, the influence of thermomechanical treatment on the mechanical properties,...     

Study of the Microstructure,Crystallographic Structure and Thermal Stability of Al–Ti–Nb Alloys Produced by Selective Electron Beam Alloying

This paper aims an investigation of the microstructure and crystallographic structure as well as the thermal stability of Al–Ti–Nb formed by selective electron beam surface alloying. The fabrication of the samples has been carried out using circular sweep mode, as two velocities of the sample movement have been chosen: V₁ = 1 cm/s and V₂ = 0.5 cm/s. The studied microstructure and crystallographic structure have been investigated by X-ray diffraction (XRD) and Scanning electron microscopy (SEM) respectively. The thermal behavior of the obtained surface alloys are evaluated by the coefficient of thermal expansion (CTE) which has been evaluated by neutron diffraction measurements at high temperature. The results show that in the earlier stages of formation, the microstructure of the intermetallic phase is mainly in the form of coarse fractions, but at the following moments they dissolve, forming separated alloyed zone and base Al substrate as the alloyed zone consists of fine (Ti,Nb)Al₃ particles dispersed in the Al matrix with small amount of undissolved intermetallic fractions. Formation of preferred crystallographic orientation as a function of the speed of specimen motion has not been observed. The performed neutron diffraction measurements show that the lattice parameters of the obtained intermetallic (Ti,Nb)Al₃ are less upshifted in comparison to pure Al. It has been found that the aluminium lattice is much more unstable at high temperatures than that of the intermetallic phase. The CTE for the intermetallic phase is 8.70 ppm/K for a axis and 7.75 ppm/K for c axis respectively while considering Al it is 12.95 ppm/K.     

Structure and Phase Composition of Ti–6Al–4V Alloy Obtained by Electron-Beam Additive Manufacturing

Russian Physics Journal - The paper presents the fabrication of Ti–6Al–4V alloy specimens using two operating modes of the electron beam additive manufacturing (EBAM). The structure,...     

Effect of nitrogen partial pressure on Al–Ti–N films deposited by arc ion plating

AlTiN films with different nitrogen partial pressures were deposited using arc ion plating (AIP) technique. In this study, we systematically investigated the effect of the nitrogen partial pressure on composition, deposition efficiency, microstructure, macroparticles (MPs), hardness and adhesion strength of the AlTiN films. The results showed that with increasing the nitrogen partial pressure, the deposition rate exhibited a maximum at 1.2 Pa. Results of X-ray photoelectron spectroscopy (XPS) analysis revealed that AlTiN films were comprised of Ti–N and Al–N bonds. XRD results showed that the films exhibited a (1 1 1) preferred growth, and AlTi₃N and TiAl_x phases were observed in the film deposited at 1.7 Pa. Analysis of MPs statistics showed MPs decreased with the increase in the nitrogen partial pressure. In addition, the film deposited at 1.2 Pa possessed the maximum hardness of 38 GPa and the better adhesion strength.     

Principles of Structure and Phase Composition Formation in Composite Master Alloys of the Al–Ti–B/B4c Systems Used for Aluminum Alloy Modification

Russian Physics Journal - The principles of formation of structure and properties of materials produced by self-propagating hightemperature synthesis (SHS) from the Al–Ti–B/B4C powder...     

The effect of Cu on precipitation in Al–Mg–Si alloys

TEM investigations of two alloys isothermally heat treated at 175°C and 260°C show how Cu additions to the Al–Mg–Si system affect precipitation. Both alloys had a solute content Mg?+?Si?=?1.3 at.%, 0.127 at.% Cu, but with Mg/Si 0.8 and 1.25. Cu-containing Guinier-Preston (GP) zones and three types of Q′ precursors are identified as most common phases at peak-hardness conditions, whereas β″ accounts for maximum 30% of the total number of precipitates. The precursors have needle (L and S precipitates) or plate (C precipitate) morphologies. They consist of different arrangements of Al, Mg and Cu atoms on a grid defined by triangularly arranged Si planes parallel with and having the same period as {100} Al planes. The Si grid is composed of nearly hexagonal sub-cells of a?=?b?=?4.05?Å, c?=?4.05?Å. The Cu arrangement on the grid is often disordered in the needle precursors. The plate precursor is ordered, with a monoclinic unit cell of a?=?10.32?Å, b?=?8.1?Å, c?=?4.05?Å, γ?=?101°.     

Mechanical Properties of Ti–Ni–Ta and Ti–Ni–Ta–Si Surface Alloys Synthesized on Titanium Nickelide Substrates

Technical Physics - The physical-mechanical properties of Ti-Ni-Ta and Ti-Ni-Ta-Si surface alloys (about 1 μm thick) synthesized on TiNi substrates by the additive thin-film electron-beam...     

Structure and Properties of SnO2–In2O3–Ag–N Coatings Formed by a Complex Method on Copper

Russian Physics Journal - The aim of this work is to analyze the structure and properties of a coating of the SnO2–In2O3–Ag–N composition formed on copper by a complex method...