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In the present work, the evolution of the microstructure in additively manufactured 17-4PH stainless steel, which was subjected to laser surface alloying with amorphous boron and nitrogen at the varying process parameters, was studied. The main aim was to improve surface hardness and hence potential wear resistance of the steel. Scanning electron microscopy, wavelength-dispersive X-ray spectroscopy (WDS), and Auger electron spectroscopy (AES) were used. It was shown that the final microstructure developed in the laser-melted zone (LMZ) is dependent on a variety of processing parameters (1 and 1.5 mm laser beam spot diameters; 200, 400, and 600 mm/min laser scan speeds), which primarily influence the morphology and orientation of the eutectic dendrites in the LMZ. It was metallographically proven that a fully eutectic microstructure, except for one sample containing 60 ± 4.2% of the eutectic, was revealed in the LMZ in the studied samples. The results of WDS and AES also confirmed alloying the LMZ with nitrogen. The formation of the boron eutectic and the supersaturation of the α-iron solid solution with boron and nitrogen (as a part of the eutectic mixture) led to enhanced microhardness, which was significantly higher compared with that of the heat-treated substrate (545.8 ± 12.59–804.7 ± 19.4 vs. 276.8 ± 10.1–312.7 ± 11.7 HV0.1).

This study investigates the phase composition, microstructure, and their influence on the properties of Mo-W-C nanocomposite films deposited by dual-source magnetron sputtering. The synthesised films consist of metal carbide nanograins embedded in an amorphous carbon matrix. It has been found that nanograins are composed of the hexagonal β-(Mo2 + W2)C phase at a low carbon source power. An increase in the power results in the change in the structure of the carbide nanoparticles from a single-phase to a mixture of the β-(Mo2 + W2)C and NaCl-type α-(Mo + W)C(0.65≤k≤1) solid-solution phases. The analysis of electrical properties demonstrates that the nanograin structure of the films favours the occurrence of hopping conductivity. The double-phase structure leads to a twofold increase in the relaxation time compared to the single-phase one. Films with both types of nanograin structures exhibit tunnelling conductance without the need for thermal activation. The average distance between the potential wells produced by the carbide nanograins in nanocomposite films is approximately 3.4 ± 0.2 nm. A study of tribomechanical properties showed that Mo-W-C films composed of a mixture of the β-(Mo2 + W2)C and α-(Mo + W)C(0.65≤k≤1) phases have the highest hardness (19–22 GPa) and the lowest friction coefficient (0.15–0.24) and wear volume (0.00302–0.00381 mm2). Such a combination of electrical and tribomechanical properties demonstrates the suitability of Mo-W-C nanocomposite films for various micromechanical devices and power electronics.

The article is aimed at identifying the influence of laser texturing and subsequent coating with a hard, wear-resistant coating AlCrSiN (nACRo®) on selected tribological properties of the analyzed tool steels for cold work, produced by conventional and powder metallurgy. The substrate from each steel was heat treated to achieve optimal properties regarding the chemical composition and the method of production of the material. Böhler K100 and K390 Microclean® steels were used. These are highly alloyed tool steels used for various types of tools intended for cold work. The obtained results show that the coefficient of friction is increased by coating, but the wear rate is lower compared to the samples which were only textured.

The present work investigates the influence of isothermal annealing on the microstructure and oxidation behavior of nanocomposite coatings. AlTiSiN/TiSiN coatings with TiSiN adhesive layer were deposited onto a high-speed steel substrate via physical vapor deposition. The coatings were investigated in the as-deposited state as well as after annealing in air at 700, 800, 900 and 1000 °C, respectively. The microstructure and morphology of the coatings were observed using scanning electron microscopy and transmission electron microscopy. The chemical composition and presence of oxidation products were studied by energy-dispersive X-ray spectroscopy. The phase identification was performed by means of X-ray diffraction. In the microstructure of the as-deposited coating, the (Ti1−xAlx)N particles were embedded in an amorphous Si3N4 matrix. TiO2 and SiO2 were found at all annealing temperatures, and Al2O3 was additionally identified at 1000 °C. It was found that, with increasing annealing temperature, the thickness of the oxide layer increased, and its morphology and chemical composition changed. At 700 and 800 °C, a Ti-Si-rich surface oxide layer was formed. At 900 and 1000 °C, an oxidized part of the coating was observed in addition to the surface oxide layer. Compared to the as-deposited sample, the oxidized samples exhibited considerably worse mechanical properties.

EN AW2099 aluminium lithium alloy, 2.0mm in thickness, was used as an experimental material. EN AW2099 belongs to the 3rd generation of aluminium lithium alloys. The third generation was developed to improve the disadvantages of the previous generation, such as anisotropy in mechanical properties, low fracture toughness, corrosion resistance and resistance to fatigue crack growth, as well. Aluminium magnesium 5087 filler wire with a diameter of 1.2mm was used for the welding. Crack free weld joints were produced after an optimization of welding parameters. The microstructure of weld metal and mechanical properties of weld joints were investigated. Equiaxed zone (EQZ) was observed at the fusion boundary. The character of grains changed in the direction towards the weld centre, from the columnar dendrite zone to equiaxed dendrite zone in the weld centre. The microstructure of the weld metal matrix consisted of -aluminium. Alloying elements enrichment was found at the inter-dendritic areas, namely copper and magnesium. The microhardness decrease in the weld metal due to a dissolution of strengthening precipitates was measured. The microhardness was slightly higher in comparison to a weld produced by a laser welding without a filler material. The tensile strength of the weld joint reached around 67% of the base material’s strength and the fracture occurred in the weld metal.

Commercially pure titanium Ti Grade 2, 2 mm in thickness, was welded to 2 mm thick nickel alloy 201 with electron beam welding. Various welding parameters were used to create the butt-welded joints. The innovation herein consists of welding two dissimilar metals that are declared non-weldable. The welding current used for electron beam welding was 40–70 mA and welding speeds were 20–50 mm/s. In this experiment, we tested two offsets of the electron beam, which were 100–300 μm to the nickel side and 200 μm to the titanium side. It was observed that the offset of the beam had no effect on the weld joint’s strength. The samples were subjected to a visual test in which longitudinal and transverse cracks were recorded along the whole weld. Only four samples retained the integrity of the joint. Microstructures of the weld joints were examined by scanning confocal and scanning electron microscopy. Energy dispersive spectroscopy (EDS) analysis confirmed the phase constitution inside the weld regions and the fusion interfaces. Tensile strength and microhardness tests were used to evaluate the mechanical parameters of the Ti/Ni welded joint. The results showed that cracking of brittle Ni–Ti intermetallic phases in electron beam welded joints occurred. The microstructure in the fusion zone’s center part was primarily NiTi and Ti2Ni. No clear correlation was found between heat input or welding parameters—welding current and welding speed—and tensile strength. The strain–tensile strength curve resulted in brittle fracturing. The hardness of the weld zone was five times higher than that of the base metal and heat-affected zone. The amount of heat input into the welded metal is as critical as the large asymmetry in heat transport that controls the process of solidification from each side of the base metal.

Drilling of Carbon Fiber-Reinforced Plastic/Titanium alloy (CFRP/Ti) stacks represents one of the most widely used machining methods for making holes to fasten assemblies in civil aircraft. However, poor machinability of CFRP/Ti stacks in combination with the inhomogeneous behavior of CFRP and Ti alloy face manufacturing and scientific community with a problem of defining significant factors and conditions for ensuring hole quality in the CFRP/Ti alloy stacks. Herein, we investigate the effects of drilling parameters on drilling temperature and hole quality in CFRP/Ti alloy stacks by applying an artificial neuron network (ANN). We varied cutting speed, feed rate, and time delay factors according to the factorial design L9 Taguchi orthogonal array and measured the drilling temperature, hole diameter, and out of roundness by using a thermocouple and coordinate measuring machine methods for ANN analysis. The results show that the drilling temperature was sensitive to the effect of stack material layer, cutting speed, and time delay factors. The hole diameter was mainly affected by feed, stack material layer, and time delay, while out of roundness was influenced by the time delay, stack material layer, and cutting speed. Overall, ANN can be used for the identification of the drilling parameters–hole quality relationship.

Due to the increased demands for drilling and cutting tools working at extreme machining conditions, protective coatings are extensively utilized to prolong the tool life and eliminate the need for lubricants. The present work reports on the effect of a second MeN (Me = Zr, Cr, Mo, Nb) layer in WN-based nanocomposite multilayers on microstructure, phase composition, and mechanical and tribological properties. The WN/MoN multilayers have not been studied yet, and cathodic-arc physical vapor deposition (CA-PVD) has been used to fabricate studied coating systems for the first time. Moreover, first-principles calculations were performed to gain more insight into the properties of deposited multilayers. Two types of coating microstructure with different kinds of lattices were observed: (i) face-centered cubic (fcc) on fcc-W2N (WN/CrN and WN/ZrN) and (ii) a combination of hexagonal and fcc on fcc-W2N (WN/MoN and WN/NbN). Among the four studied systems, the WN/NbN had superior properties: the lowest specific wear rate (1.7 × 10−6 mm3/Nm) and high hardness (36 GPa) and plasticity index H/E (0.93). Low surface roughness, high elastic strain to failure, Nb2O5 and WO3 tribofilms forming during sliding, ductile behavior of NbN, and nanocomposite structure contributed to high tribological performance. The results indicated the suitability of WN/NbN as a protective coating operating in challenging conditions.

A commercially available pyrotechnic igniter was used according to the EN 14034 and ASTM E1226a Standards to study the explosiveness of dispersed dusts. Its pyrotechnic composition consists of 1.2 g of zirconium (40% wt.), barium peroxide (30% wt.) and barium nitrate (30% wt.). The energy released during the combustion of that amount of composition is 5 kJ. The article investigates the influence of aging of the pyrotechnic composition in the igniter on its initiation parameters. In the study, igniters of different years from date of manufacture were used: Igniter 1, manufactured in 2021 (less than 1 year from date of manufacture), and Igniter 2 (more than 2 years from date of manufacture). The study was performed in the KV 150M2 explosion chamber with a volume of 365 L and the 20 L sphere chamber with a volume of 20 L. A standard sample of Lycopodium clavatum was used in the KV 150M2 explosion chamber. Magnesium and benzoic acid were used as the samples in the 20 L sphere explosion chamber. The experiment showed that the explosion pressure Pmax of the igniter with more than 2 years from date of manufacture decreased by up to 10%, while the value of the explosion constant Kst decreased by up to 40%. The attained results proved that aging of igniters affects their explosion parameters and measurement accuracy.

The paper examines the surface functionalization of a new type of Ti-graphite composite, a dental biomaterial prepared by vacuum low-temperature extrusion of hydrogenated-dehydrogenated titanium powder mixed with graphite flakes. Two experimental surfaces were prepared by laser micromachining applying different levels of incident energy of the fiber nanosecond laser working at 1064 nm wavelength. The surface integrity of the machined surfaces was evaluated, including surface roughness parameters measurement by contact profilometry and confocal laser scanning microscopy. The chemical and phase composition were comprehensively evaluated by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analyses. Finally, the in vitro tests using human mesenchymal stem cells were conducted to compare the influence of the laser processing parameters used on the cell’s cultivation and osteo-differentiation. The bioactivity results confirmed that the surface profile with positive kurtosis, platykurtic distribution curve and higher value of peaks spacing exhibited better bioactivity compared to the surface profile with negative kurtosis coefficient, leptokurtic distribution curve and lower peaks spacing.

The aim of the research was to characterize the soldering alloy type Zn–Al–Cu and study the fluxless ultrasonic soldering of the combination of aluminum alloy type Al7075 with copper substrate. The Zn–Al–Cu solder is of the close-to-eutectic type with two phase transformations: the eutectic transformation at 378 °C and the eutectoid transformation at 285 °C. The solder microstructure is formed of a matrix composed of the solid solutions of aluminum (Al) and zinc (Zn) in which the copper phases CuZn4 and CuAl2 are precipitated. The shear strength of the soldering alloy type Zn5Al with copper addition reaches values from 167 to 187 MPa and it depends on the copper content in the solder. The bond with aluminum alloy type Al7075 is formed due to the solubility of Al in zinc solder at the formation of solid solution Al. Contrary to this observation, the bond with the copper substrate is in this case formed due to the interaction of zinc and aluminum with the copper substrate. Two new intermetallic phases, namely Al(Cu,Zn)2 and Cu3.2Zn0.7Al4.2, were formed. The average shear strength of Al7075/Zn5Al3Cu/Cu joints attained was 134.5 MPa. For comparison, the Cu/Zn5Al3Cu/Cu joint attained an average shear strength of 136.5 MPa.

In this article, the effect of process parameters on the microstructure and mechanical properties of AW5083 aluminum alloy weld joints welded by a disk laser were studied. Butt welds were produced using 5087 (AlMg4.5MnZr) filler wire, with a diameter of 1.2 mm, and were protected from the ambient atmosphere by a mixture of argon and 30 vol.% of helium (Aluline He30). The widest weld joint (4.69 mm) and the highest tensile strength (309 MPa) were observed when a 30 L/min shielding gas flow rate was used. Conversely, the narrowest weld joint (4.15 mm) and the lowest tensile strength (160 MPa) were found when no shielding gas was used. The lowest average microhardness (55.4 HV0.1) was recorded when a 30 L/min shielding gas flow rate was used. The highest average microhardness (63.9 HV0.1) was observed when no shielding gas was used. In addition to the intermetallic compounds, β-Al3Mg2 and γ-Al12Mg17, in the inter-dendritic areas of the fusion zone (FZ), Al49Mg32, which has an irregular shape, was recorded. The application of the filler wire, which contains zirconium, resulted in grain refinement in the fusion zone. The protected weld joint was characterized by a ductile fracture in the base material (BM). A brittle fracture of the unshielded weld joint was caused by the presence of Al2O3 particles. The research results show that we achieved the optimal welding parameters, because no cracks and pores were present in the shielded weld metal (WM).

Deoxidized oxygen free copper C12200, 1 mm in thickness, was welded to 1-mm thick AISI 304 stainless steel with disk laser. The butt-welded joints were produced with different welding parameters. Full factorial design of experiment (DoE) approach consisting of three factors and two levels was utilized. Laser powers used for welding were 1.3 and 1.9 kW and welding speeds of 20 and 30 mm/s. Two beam offsets were tested, namely, 100 μm toward copper side and 200 μm toward AISI 304 steel. It was found that beam offset possesses the largest influence on the welded joints’ tensile strength. Tensile strengths attained values more than 3.7 times higher in comparison to the AISI 304 steel beam offset. When lower laser power was used, the higher tensile strength was attained for copper sheet offset. Higher microhardness was observed when laser beam was offset to AISI 304 steel side. The average microhardness of the weld metal was higher than that of the weaker base material, copper sheet. Energy dispersive X-ray spectroscopy (EDS) analysis confirmed the heterogeneity in elemental composition across the welded joint interface, being lower when laser beam was offset to AISI 304 steel side. On the other hand, the copper content dropped to the average composition of weld metal at the distance of about 140 μm from copper-weld metal interface.

In this work, the effect of rapid quenching from the partially liquid and solid condition is studied on the as-cast microstructure, tensile properties and fracture features of a secondary hypereutectic Al-18%Si-2%Cu alloy. For comparison purposes, the same ingots of 50 mm in diameter and 300 mm in height were also fabricated using conventional chill casting. The microstructure of the samples was subjected to detailed characterisation using scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The tensile properties and fracture were also evaluated. A significant grain refinement of the eutectic constituents (α (Al) + Si), as well as primary silicon and intermetallics accompanying coarse plate and Chinese script with a well-dispersed morphology transition for the intermetallics, was observed in the alloy subjected to the rapid quenching. The connection between primary and eutectic silicon was shown metallographically, confirming the fact that primary silicon served as a nuclei site for eutectic silicon. The microstructure refinement, together with a favourable morphology transition, resulted in greatly enhanced tensile properties and the more ductile fracture behaviour of the studied alloy.

Biocompatible materials with excellent mechanical properties as well as sophisticated surface morphology and chemistry are required to satisfy the requirements of modern dental implantology. In the study described in this article, an industrial-grade fibre nanosecond laser working at 1064 nm wavelength was used to micromachine a new type of a biocompatible material, Ti-graphite composite prepared by vacuum low-temperature extrusion of hydrogenated-dehydrogenated (HDH) titanium powder mixed with graphite flakes. The effect of the total laser energy delivered to the material per area on the machined surface morphology, roughness, surface element composition and phases transformations was investigated and evaluated by means of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), confocal laser-scanning microscopy (CLSM) and X-ray diffraction analysis (XRD). The findings illustrate that the amount of thermal energy put to the working material has a remarkable effect on the machined surface properties, which is discussed from the aspect of the contact properties of dental implants.

Nanocomposite AlCrSiN hard coatings were deposited on the cemented carbide substrates with a negative substrate bias voltage within the range of −80 to −120 V using the cathodic arc evaporation system. The effect of variation in the bias voltage on the coating-substrate adhesion and nanohardness was investigated. It was clear that if bias voltage increased, nanohardness increased in the range from −80 V to −120 V. The coating deposited at the bias voltage of −120 V had the highest nanohardness (37.7 ± 1.5 GPa). The samples were prepared by brushing and wet microblasting to finish a surface and prepare the required cutting edge radii for the tool life cutting tests and the coating adhesion observation. The indents after the static Mercedes indentation test were studied by scanning the electron microscope to evaluate the coating-substrate adhesion. The longer time of edge preparation with surface finishing led to a slight deterioration in the adhesion strength of the coating to the substrate. The tool wear of cemented carbide turning inserts was studied on the turning centre during the tool life cutting test. The tested workpiece material was austenitic stainless steel. The cemented carbide turning inserts with larger cutting edge radius were worn out faster during the machining. Meanwhile, the tool life increased when the cutting edge radius was smaller.

The microstructure, phase constitution, and corrosion performance of as-solidified Al70Pd25Co5 and Al74Pd12Co14 alloys (element concentrations in at.%) have been investigated in the present work. The alloys were prepared by arc-melting of Al, Pd, and Co lumps in argon. The Al74Pd12Co14 alloy was composed of structurally complex εn phase, while the Al70Pd25Co5 alloy was composed of εn and δ phases. The corrosion performance was studied by open circuit potential measurements and potentiodynamic polarization in aqueous NaCl solution (3.5 wt.%). Marked open circuit potential oscillations of the Al70Pd25Co5 alloy have been observed, indicating individual breakdown and re-passivation events on the sample surface. A preferential corrosion attack of εn was found, while the binary δ phase (Al3Pd2) remained free of corrosion. A de-alloying of Al from εn and formation of intermittent interpenetrating channel networks occurred in both alloys. The corrosion behavior of εn is discussed in terms of its chemical composition and crystal structure. The corrosion activity of εn could be further exploited in preparation of porous Pd−Co networks with possible catalytic activity.

The aim of the research was to characterize the soldering alloy In–Ag–Ti type, and to study the direct soldering of SiC ceramics and copper. The In10Ag4Ti solder has a broad melting interval, which mainly depends on its silver content. The liquid point of the solder is 256.5 °C. The solder microstructure is composed of a matrix with solid solution (In), in which the phases of titanium (Ti3In4) and silver (AgIn2) are mainly segregated. The tensile strength of the solder is approximately 13 MPa. The strength of the solder increased with the addition of Ag and Ti. The solder bonds with SiC ceramics, owing to the interaction between active In metal and silicon infiltrated in the ceramics. XRD analysis has proven the interaction of titanium with ceramic material during the formation of the new minority phases of titanium silicide—SiTi and titanium carbide—C5Ti8. In and Ag also affect bond formation with the copper substrate. Two new phases were also observed in the bond interphase—(CuAg)6In5 and (AgCu)In2. The average shear strength of a combined joint of SiC–Cu, fabricated with In10Ag4Ti solder, was 14.5 MPa. The In–Ag–Ti solder type studied possesses excellent solderability with several metallic and ceramic materials.

This paper presents an analysis of the properties of resistance spot welds between low carbon steel and austenitic CrNi stainless steel. The thickness of the welded dissimilar materials was 2 mm. A DeltaSpot welding gun with a process tape was used for welding the dissimilar steels. Resistance spot welds were produced with various welding parameters (welding currents ranging from 7 to 8 kA). Light microscopy, microhardness measurements across the welded joints, and EDX analysis were used to evaluate the quality of the resistance spot welds. The results confirm the applicability of DeltaSpot welding for this combination of materials.