This study discusses the effect of a duplex aging + nitriding process on the wear resistance of an aged double-phase titanium alloy, BT22. Nitriding was applied simultaneously with the heat treatment of the alloy, which is advantageous over the conventional heat and surface treatment methods applied to titanium alloys. According to the results, the thickness of the case depth of the nitrided samples was 40–50 μm. Moreover, nitrogen was uniformly dispersed in the substrate, which was indicated by the hardness tests. The average microhardness of the substrate material was 300 HV_0.01, while the hardness of the top layer was 1190 HV_0.01, which is an almost four-fold increase. The applied duplex treatment substantially affected the wear performance of the tested alloy. For the untreated alloy, the maximum coefficient of friction was 0.8, while in the surface-modified sample, the maximum fluctuations reached 0.6. The abrasive wear process was dominant in the nitrided samples, while delamination and adhesive wear were observed for the untreated specimens. The nitrided alloy exhibited double the wear resistance of the untreated samples. The proposed treatment does not require additional time or energy consumption, providing a substantial technological advantage over conventional methods. Though the alpha case reduces the mechanical performance of titanium, the nitriding of only the component sections intended to withstand friction will have a positive effect.

Three types of sintered alloys were fabricated based on cobalt, nickel and high-temperature alloy ZhS32-VI matrix with titanium carbide strengthening phase. TiC content was in a range of 30–50 vol. %. The melting temperatures of alloys are higher than 1320°C, and they may undergo undamaged through all technological procedures together with turbine blades, including soldering and outgassing. DSC analyses indicates no additional thermal effects until melting, which confirms their structural stability. The examinations of microstructure revealed three types of constituents – TiC particles, matrix solid solution and blow outs – structural defects having negative effects on all the studied properties. It was found that heat resistance of nickel based sintered alloys at the temperature of 1100°C is superior as compared with the alloys based on cobalt and alloy ZhS32-VI. It has been established that wear resistance in conditions of fretting wear at temperatures of 20, 850, 950 and 1050°C of sintered alloy with ZhS32-VI matrix is mostly superior as compared with the other alloys. The properties of produced alloys allow to use them for manufacturing of components of friction couples operating in conditions of high temperature fretting wear, including protective pads of turbine blades top shrouds contact faces.

Textured surfaces with partially regular micro relief (PRMR) are reported to be an effective means to control lublication. It was found they are good wear debris trap and suppliers of lubricant directly to the actual friction area. Their tribological properties depend on the clearance between mating surfaces, relative slip speed, direction of motion. These parameters change the lubrication regime, and vice versa changing geometry of PRMR it is possible to predict and control lubrication regime for given conditions. Application of micro textured surface is prospective for high precision sliding units – valve slides of oil and hydraulic systems, faces of gear pump gears, ring-to-cylinder interface of aircraft reciprocating engines etc. providing high service life. On other side, changing texture parameters it is possible to stop the leakage of fluid through the gap, what may be efficiently utilized in aircraft non-contacting mechanical (hydrodynamic and hydrostatic) seals of gas compressors and gear mechanisms. This paper discloses some peculiarities of transition lubrication regimes for textured surfaces in lubricated contact.

This paper focuses on the microstructure and tribological properties of novel hardfacing alloy based on Fe-C-Mn-B doped with Ni, Cr, and Si. The 4 mm-thick coating was deposited on the AISI 1045 carbon steel by the MIG-welding method using flux-cored wires in three passes. The transition zone thickness between the weld layers was ~80 μm, and the width of the substrate-coating interface was 5–10 μm. The following coating constituents were detected: coarser elongated M₂B borides, finer particles of Cr₇C₃ carbides, and an Fe-based matrix consisting of ferrite and austenite. The nanohardness of the matrix was ~5–6 GPa, carbides ~16–19 GPa, and borides 22–23 GPa. A high cooling rate during coating fabrication leads to the formation of a fine mesh of M₇C₃ carbides; borides grow in the direction of heat removal, from the substrate to the friction surface, while in the transition zone, carbides become coarser. The dry sliding friction tests using a tribometer in PoD configuration were carried out at contact pressure 4, 7, 10, and 15 MPa against the AISI 1045 carbon steel (water-quenched and low-tempered, 50–52 HRC). The leading wear phenomenon at 4 and 7 MPa is fatigue, and at 10 and 15 MPa it is oxidation and delamination.

The aim of this paper is to investigate the effect of TiC addition on the microstructure, microhardness, and wear resistance of the medium-entropy alloy Co37Cr28Ni31Al2Ti2, which is suitable for applications in aerospace, automotive, and energy industries due to its high strength and wear resistance. The samples containing 0, 10, 20, and 40 wt.% of TiC were synthesized. The alloy’s microstructure changes significantly with the addition of TiC particles: they are uniformly dispersed in the FCC matrix, effectively increasing the Vickers hardness from 439 HV for the base alloy to 615 HV for the 40% TiC alloy. The four alloys were subjected to reciprocating dry sliding friction tests at loads of 2 N, 5 N, and 10 N. The wear volumes of the base alloy at these loads were 2.7 × 107, 4.6 × 107, and 1.1 × 108 μm3, respectively. The experimental results indicate that adding TiC greatly improves the wear resistance of the alloy by increasing the hardness and forming an oxide protective film. This study highlights the potential for developing alloys with excellent tribological properties for demanding application scenarios.