Kamil Ochał

This paper presents the results of a study on the application of a slurry method to produce aluminide coatings on aircraft engine turbine blades. The coating was produced on ZS6K alloy blades by 1, 2 and 3 times spray painting with intermediate drying followed by diffusion annealing in Ar atmosphere for 2, 4 and 6 hours at 900, 950 and 1000°C. The coatings were evaluated with consideration of thickness structure and aluminum content. The results indicated that the use of single-painting did not allow - regardless of temperature and annealing time - to obtain a uniform aluminide coating. The use of two-time painting and diffusion annealing at time 4 hours makes it possible to obtain coatings with a thickness of 60–80 μm containing 26–30 wt. % of aluminum. Three-coat painting makes it possible to obtain coatings close to 100 μm thick containing 28–32 wt. % of aluminum.

Thermal spraying is playing an increasingly important role among coating manufacturing methods because of its properties and ecology. An obstacle to their development is the price of the available equipment used in this process. The article presents the concept of making individual elements of a powder feeder by 3D printing. The designs are equipped with a volumetric feeding system using a disk driven by an electric motor and a worm gearbox. The individual elements of the feeder were designed and based on the drawings; they were made using several types of 3D printers. The design and fabrication were limited to the use of a small number of parts made of metal including little machining. In the following part, a prototype of the feeder was made and tested. It was shown to have correct characteristics of its operation and, in particular, correct linear characteristics of powder feed rate from disk speed similarly to commercial devices. Tests of the made feeder indicate the possibility of its use in thermal spraying systems.

1.4418 hardened stainless steel (SS) is widely used in mechanical engineering because of its high functional properties. They can also be enhanced by procuring improvements in the state of the surface layer (SL) and, above all, in the factors of its strengthening, among others the average size of coherent scattering regions (ASCSR), dislocation density (DD), residual stresses (RS) of first and second orders, and relative micro-deformations of the crystal lattice (RMCL). This study investigates the effect of cutting speed (v_c) ranging from 100 to 250 m/min and feed rate (f) ranging from 0.005 to 0.25 mm/rev on the indicators of SL condition after finish turning the steel tested. A reduction in ASCSR values below 8 nm was obtained for v_c = 100–135 m/min, while an increase of ~ 20% was obtained for 180–250 m/min and with the f ranging from 0.2 to 0.25 mm/rev. An increase in RMCL of ~ 90% was registered for v_c = 170–230 m/min and f = 0.2–0.25 mm/rev. A decrease in DD below 10⁹ cm⁻² was obtained for v_c = 180–250 m/min and its ~ 25% increase for v_c = 100–135 m/min. A high correlation between ASCSR and DD was shown. In the deformed material, the dislocation’s resistance to motion increases in proportion to the increase in its density. A high linear correlation coefficient in the range of 0.8–0.9 is found between ASCSR, DD, and first-order RS on the one hand, and Sa and Sz surface texture parameters, which are used in the industry to assess product quality, on the other. Additionally, the effect of plastic side flow (PSF) was observed and described. When machining with v_c = 119 m/min and f = 0.22 mm/rev, the intense plastic deformation of the material causes outflow and shearing of the surface micro-hills. Favorable compressive stresses (below − 100 MPa) were registered in the range of v_c = 225–250 m/min at f = 0.005–0.05 m/rev and 0.2–0.25 mm/rev, as well as v_c = 115–180 m/min and f = 0.05–0.17 mm/rev. The study proved the existence of a relationship between the cutting parameters and indicators of the thin crystalline structure of SL. This means that by proper controlling of these parameters, it is possible to obtain such a state of the SL workpiece, which will ensure its long-term use.

This study investigates residual stresses in stiffening ribs of composite materials formed by stamping in a punch-die system. Using two-dimensional X-ray diffraction (XRD), we measured residual stresses on both the anterior and posterior sides. Three LITECOR^® composite types, with core thicknesses of 0.8, 1.25, and 1.6 mm, were examined. Results indicate that as core thickness increases, residual stress values decrease on both sides. Notably, anterior side stresses on the y-axis are relatively higher (1027–1199 MPa) compared to the x-axis, exceeding posterior side values (998–1083 MPa) at 0.8 mm core thickness. Moreover, the study compares these values with Single Point Incremental Forming (SPIF) and finds that SPIF generally yields lower stress values for all core thicknesses. These findings suggest that SPIF is favourable for achieving minimal residual stress in LITECOR^® composites. Addressing residual stresses is crucial for enhancing structural integrity and extending the service life of sandwich panels and composite materials.

This article presents the influence of the brushing process on residual stress and surface roughness of EN AW-2024-T3 aluminum alloy joints welded using the Friction Stir Welding (FSW) method. Butt joints with thicknesses of 2 mm were brushing with using ceramic brush. The aim of the study was...

This article presents the influence of the Shot Peening (SP) process on residual stress and surface roughness of AMS 5504 joints welded using the Tungsten Inert Gas (TIG) method. Thin-walled steel structures are widely used in the aviation and automotive industries, among others. Unfortunately, the fatigue properties become worse during the welding process. Samples of 1 mm-thick AMS 5504 steel plates were first prepared using TIG welding and then strengthened by the Shot Peening (SP) process. The technological parameters of the SP process were changed in the range of time t from 2 min to 4 min and of pressure p from 0.4 MPa to 0.6 Mpa. The residual stresses were measured by X-ray diffraction in three zones: fusion zone (FZ), heat-affected zone (HAZ) and base metal (BM). The results showed that SP introduced compressive residual stresses in all of the zones measured, especially in the FZ. The greatest value of compressive residual stresses σ = −609 MPa in the FZ was observed for the maximum parameters of SP (p = 0.6 MPa, t = 4 min). The increase in value of residual stress is about 580% when compared to welding specimens without treatment. As a result of shot peening in the FZ, the mean roughness value Ra decreased in range 63.07% to 77.67% in the FZ, while in the BM increased in range 236.87% to 352.78% in comparison to specimen without treatment. Selected surface roughness parameters in FZ and BM were analyzed using neural networks. In FZ, it was demonstrated that the most correlated parameters with residual stresses are Rt and Rsk. On the other hand, in the BM zone, the most correlated parameters were Rv, Rt and Rq. This enables the estimation of stresses in the welded joint after SP on the basis of selected roughness parameters.

Low weight and high strength are significant factors in the current decade’s spread of composite sandwich materials. Previous studies have proven that forming stiffening ribs in these materials through the Single Point Incremental Forming (SPIF) process is possible and gives encouraging results. On the other hand, knowledge of residual stress (RS) values that form during the manufacturing process is essential, as they may affect the structural integrity of manufactured elements, whether in compression or tension. The investigation of the RS in the composite materials formed by the SPIF process using the XRD method was very limited in the previous studies, so this research aims to apply the X-ray diffraction (XRD) method to determine RS on the part of the LITECOR^® sandwich material formed using SPIF. LITECOR^® consists of a plastic core between two layers of steel. In this study, three types of LITECOR^® were used with differing plastic core thicknesses of 0.8, 1.25, and 1.6 mm, while the steel layers’ thickness remained the same at 0.3 mm. The axial and traverse RSs were measured in five positions on both sides of the formed part. It was found that the achieved RSs varied from tensile to compressive along the formed regions. It was found that the residual stress values in both directions were inversely proportional to the thickness of the plastic core. It was noted that the highest RS values were in the unformed base metal, after which the RS was reduced on both sides of the SPIF-formed region, followed by a rise in the RS at the concave of the SPIF-formed region. The maximum measured RS for X-axes was 1041 MPa, whereas, for Y-axes, it was 1260 MPa, both of which were recorded on the back side at a thickness of t = 0.8 mm.

The influence of cooling conditions and surface topography after finish turning of Ti6Al4V titanium alloy on corrosion resistance and surface bioactivity was analyzed. The samples were machined under dry and minimum quantity lubrication (MQL) conditions to obtain different surface roughness. The surface topographies of the processed samples were assessed and measured using an optical profilometer. The produced samples were subjected to electrochemical impedance spectroscopy (EIS) and corrosion potential tests (E_corr) in the presence of simulated body fluid (SBF). The surface bioactivity of the samples was assessed on the basis of images from scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analysis. The inspection of the surfaces of samples after turning under dry and MQL conditions revealed unevenly distributed precipitation of hydroxyapatite compounds (Ca/P) with a molar ratio in the range of 1.73–1.97. Regardless of the cutting conditions and surface roughness, the highest values of E_corr ~0 mV were recorded on day 7 of immersion in the SBF solution. The impedance characteristics showed that, compared to the MQL conditions, surfaces machined under dry conditions were characterized by greater resistance and the presence of a passive layer on the processed surface. The main novelty of the paper is the study of the effect of ecological machining conditions, namely, dry and MQL cutting on the corrosion resistance and surface bioactivity of Ti6Al4V titanium alloy after finish turning. The obtained research results have practical significance. They can be used by engineers during the development of technological processes for medical devices made of Ti6Al4V alloy to obtain favorable functional properties of these devices.

Due to their excellent mechanical properties, Co-based alloys are one of the main candidates to replace Ni-based alloys in high temperature application. Knowledge about oxidation resistance of Co-based alloy MAR M-509 and the extent of its aluminizing on its oxidation resistance is limited. Therefore, in the present study, an aluminide layer was manufactured by low activity chemical vapor deposition (LA-CVD) on MAR M-509. Aluminized and uncoated alloys were investigated in terms of oxidation kinetics and oxidation resistance during isothermal and cyclic oxidation at 1000 and 1100 °C. Material in the as-cast and after exposure was analyzed using scanning electron microscopy (SEM), thermogravimetry (TG) and glow-discharge optical emission spectrometry (GD-OES). Obtained results allowed for elucidating of degradation mechanism including nitridation process of carbides for MAR M-509. It was found that aluminizing of MAR M-509 significantly decreases its oxidation kinetics by the factor of 2.5 and 1.5 at 1000 and 1100 °C respectively. Moreover, the suppression of identified degradation mechanism in case of aluminized alloy was found until occurrence of breakaway oxidation of the aluminide layer. It was also proposed that further increase in oxidation resistance can be successively achieved by an increase in aluminide layer thickness.