Coordinates: 56°28′35″N 85°02′38″E / 56.4765°N 85.044°E / 56.4765; 85.044Institute of Strength Physics and Materials Science of the Siberian Division of the Russian Academy of Sciences—one of the institutes of the Tomsk Research Center of the Siberian Division of the Russian Academy of Sciences. It is located in Tomsk Academic City. The Institute consists of 5 buildings with a total area of 18,487 square meters. The Institute has 15 research laboratories, the center of collective use "Nanotech", the international centre for research on physical mesomechanics, materials, the Interdisciplinary Science and Technology Center "Welding", the Testing Laboratory "Metal-Test", and 2 scientific and technological departments..
A molecular dynamics study of structural and phase changes in bcc single crystals and Fe95Ni05 samples with a two–phase gradient–grained structure under shock loading was performed. Grains of the simulated samples with the fcc lattice contained lamellas with a bcc structure and had a pronounced texture. It was shown that the shock wave profile splits into three fronts, which form three zones with characteristic structural rearrangements: elastic, plastic, and plastic/phase. Differences in the velocities of the three fronts lead to a change in the sizes of the formed zones during shock wave propagation. Thus, the size of the plastic change zone increases due to the lag of the plastic/phase rearrangement front. An increase in the grain size gradient of the sample due to smaller grains leads to a significant decrease in the size of the plastic zone. This behavior is due to the suppression of dislocation nucleation in small grains. It is shown that the orientation of the bcc lattice relative to the direction of the shock loading significantly affects the intensity of phase transformations. When the shock wave propagates along the [110] crystallographic direction, the most active phase transitions occur than for the [111] and [112] orientations. Release waves also initiate phase transformations behind the front of their propagation.
The phase composition and microstructure of sintered powder materials based on multicomponent mixtures of Ti + Al + (Fe + Fe2O3), where one of the components is an oxidized steel swarf powder, has been studied. Two variants of the ratio of titanium and aluminum with the same volume content of swarf powder are considered. It was found that the presence of iron oxide in the initial swarf powder does not guarantee the formation of separate aluminum oxide phases. During vacuum sintering, both in the first version of the composition and in the second one, iron aluminides are mainly formed. The formation of ternary intermetallides TiFe2Al and complex oxides FeTiO3 was also observed.
The microstructure, phase composition, and tribological properties of coatings deposited on beryllium bronze to enhance its wear resistance were investigated. Composite and gradient Cu - Ti coatings, as well as single-layer and multilayer TiN and CrN / TiN coatings, were examined. It was found that composite and gradient Cu - Ti coatings exhibit a multiphase structure with either a uniform or gradient titanium distribution across the coating cross-section, depending on the ion-plasma spraying parameters. Multilayer CrN / TiN coatings displayed a well-defined layer periodicity, with individual layer thicknesses of 250 nm (16-layer coating) and 125 nm (32-layer coating). The single-layer TiN coating featured a columnar microstructure and had a total thickness of 4 μm. To enhance the adhesion of TiN and CrN coatings to the substrate, a Cu - Ti interlayer was applied, reducing interfacial stresses and improving bond strength. Scratch tests confirmed good adhesion for all coatings, with the coatings sustaining loads ranging from 10 N (single-layer and 16-layer coatings) up to 30 N (CrN coating with a Cu - Ti interlayer). Tribological tests revealed that most coatings wear via a microabrasive friction mechanism, except for the composite and gradient Cu - Ti coatings, which fail through an adhesive-brittle mechanism. The 32 - layer CrN / TiN coating and the coatings with a Cu - Ti interlayer exhibited the highest wear resistance. The findings demonstrate that multilayer architectures and Cu - Ti interlayers significantly enhance the mechanical and tribological properties of beryllium bronze coatings, making them promising for high-load and high-wear applications.
The paper presents a description for two-level model of coating synthesis on a substrate with separation of physical processes by spatial scales. This model fits the case of laser technology of a composite with the strengthening particles in-situ synthesized. The temperature field is described by a macro-problem. The variation in phase composition is modeled at the level of reaction cells within the reactive diffusion theory. These problems are interrelated. The quasi-stationary regime of synthesis is rather exception than a rule. It was shown that the dynamics for samples of various sizes are different. The conclusion on the process options in a controlled quasistationary regime can be drawn only after evaluating the spatial scales and numerical simulations.
Developing of wire-feed additive manufacturing process to fabricate high-strength and wear-resistant titanium matrix composites with reduced production time and high cost-effectiveness is challenging. This study demonstrates the ability to produce TiB reinforced Ti-6Al-4V composites using the wire-feed electron beam additive technology. The effect of boriding temperature of titanium feedstock on the microstructure and phase composition of the in-situ TiB/Ti-6Al-4V composites is studied using scanning electron microscopy and X-ray diffraction analysis. Different morphologies of TiB precipitates within prior beta grains and along their boundaries are revealed in 3D-printed 1.0 vol% TiB/Ti-6Al-4V and 7.8 vol% TiB/Ti-6Al-4V composites. An increase in the volume fraction of TiB whiskers is shown to enhance both the hardness and scratch resistance of TiB-reinforced Ti-6Al-4V composites. The effect of the TiB whiskers on the ploughing behavior during scratch testing is discussed.
