Tungsten is the prime candidate material for plasma facing components of future fusion devices. Plasma spraying, with its ability to coat large areas, including non-planar surfaces, with a significant thickness, is a prospective fabrication technology for components subject to moderate heat loads, e.g., the first wall of the Demonstration Reactor (DEMO). The functionality of such coatings is critically dependent on their adhesion to the underlying material. This in turn, is influenced by a variety of processing-related factors, chief among them being the state of the interface. In this study, the effects of two factors—surface roughness and the presence of thin interlayers—were investigated. Two different levels of roughness of steel substrates were induced by grit blasting, and two thin interlayers—titanium (Ti) and tungsten (W)—were applied by physical vapor deposition prior to plasma spraying of W by a Water Stabilized Plasma (WSP) torch. Coating adhesion was determined by a shear adhesion test. The structures of the coatings and the interfaces, as well as the characteristics of the fractured surfaces, were observed by SEM.

The research and development of materials suitable for hydrogen storage has received a great deal of attention worldwide. Due to the safety risks involved in the conventional storage of hydrogen in its gaseous or liquid phase in containers and tanks, development has focused on solid-phase hydrogen storage, including metals. Light metal alloys and high-entropy alloys, which have a high potential for hydrogen absorption/desorption at near-standard ambient conditions, are receiving interest. For the development of these alloys, due to the complexity of their compositions, a computational approach using CALPHAD (Calculation of Phases Diagrams) and machine learning (ML) methods that exploit thermodynamic databases of already-known and experimentally verified systems are being increasingly applied. In order to increase the absorption capacity or to decrease the desorption temperature and to stabilize the phase composition, specific material preparation methods (HEBM—high-energy milling, HPT—high-pressure torsion) referred to as activation must be applied for some alloys.

The paper deals with evaluation of single and multilayer layer PVD coatings based on Cr and Ti widely used in tool application. Additionally, W and WN based coating which are not so widespread were designed and deposited as functionally graded material. The coatings properties were evaluated from the point of view of hardness and adhesion. The hardness measuring was carried out using nanoindentation method. The scratch test was performed to test adhesion. Moreover, the presence of metallic interlayer in functionally graded materials further increases the coating adhesion by gradually approaching its composition to the substrate. Coatings consisting of W and WN have showed very good adhesion. With regard to the results of the scratch test, the multilayer coatings of CrN, TiN and WN have increased adhesion and can be assumed to have their protective function improved. Results will be appliedin development of functionally graded layers for functionally graded materials.

The ability of cryogenic treatment to improve tool steel performance is well established; however, the selection of optimal heat treatment is pivotal for cost reduction and extended tool life. This investigation delves into the influence of distinct cryogenic and tempering treatments on the hardness, fracture toughness, and tribological properties of Vanadis 6 tool steel. Emphasis was given to comprehending wear mechanisms, wear mode identification, volume loss estimation, and detailed characterization of worn surfaces through scanning electron microscopy coupled with energy dispersive spectroscopy and confocal microscopy. The findings reveal an 8–9% increase and a 3% decrease in hardness with cryogenic treatment compared to conventional treatment when tempered at 170 °C and 530 °C, respectively. Cryotreated specimens exhibit an average of 15% improved fracture toughness after tempering at 530 °C compared to conventional treatment. Notably, cryogenic treatment at −140 °C emerges as the optimum temperature for enhanced wear performance in both low- and high-temperature tempering scenarios. The identified wear mechanisms range from tribo-oxidative at lower contacting conditions to severe delaminative wear at intense contacting conditions. These results align with microstructural features, emphasizing the optimal combination of reduced retained austenite and the highest carbide population density observed in −140 °C cryogenically treated steel.

The subject of the research is the possibility of using laser surface hardening to modify the tribological properties of ADI castings. ADI cast irons are a very progressive material; these cast irons find their application (due to their characteristic properties) in demanding applications. In these applications, the tribology of their surface is an essential parameter. This research focused on the change in tribological properties due to laser hardening of the surface layers. ADI cast iron samples processed at different isothermal holding temperatures were selected for the experiment. This is because these temperatures have a major influence on the initial structure (before laser exposure), which also affects the laser hardening process. To analyze the structural changes, metallographic examinations were performed. The microhardness was also measured on each sample in relation to the distance from the surface. The samples were also subjected to a tribological test (linear reciprocating tribometer) during which the coefficient of friction was recorded. The surface conditions after the tribological experiment were evaluated using an electron microscope. Tribological experiments revealed very different behavior of laser-hardened ADI cast iron surfaces depending on their isothermal holding temperature. At the same time, a homogeneous martensitic layer on the surface (a consequence of the relatively uniform distribution of carbon in the initial ausferritic structure) was achieved by laser, which contributed to a significant increase in hardness and wear resistance. A trend of decreasing friction coefficient as a function of isothermal holding temperature was observed for non-laser-hardened surfaces. This phenomenon supports the theory of a possible martensitic transformation of the high-carbon austenite contained in the structure of ADI castings.

Examples of failure of mechanical parts on account of the microstructural defects or heterogeneity are described. The evaluation of defect problematic was carried out using light and scanning electron microscopy. The root detected cause of problems was in a form of coarse particles in the microstructure, intensive line spacing or banding in the material. The influence of combination of intensive stress and inappropriate orientation of parts towards the direction of forming of semi-products was often observed. A rigorous approach to the material selection and the appropriate quality control of semi-products has to be considered to prevent the risk of a failure of engineering parts.