Al-Al3Ni in-situ composites were formed on cold-worked aluminum by adding nickel powders in the pre-fabricated grooves and applying 2, 4, and 6 passes of friction stir processing (FSP). The treated specimens were characterized using SEM equipped with EDS, XRD, and microhardness tests. Shear punch tests (SPT) were also conducted at a loading speed of 0.25 mm/min. FSP of the as-received material reduced the hardness, yield shear strength (YSS), and ultimate shear strength (USS). Nevertheless, the hardness values of the fabricated composites were higher than those of the as-received material. Moreover, increasing the number of FSP passes further improved the composites' hardness, YSS, and USS. The composites produced by 6 passes of FSP showed a hardness increase of approximately 65% and a USS of about 75% higher compared to that of the as-received aluminum. The tribological behaviors of the composites and as-received material were also examined against AISI 52100 steel disc (similar to 850 HV). The presence of Al3Ni particles resulted in a reduced wear rate but increased the friction coefficient. After 500 m of sliding, the wear rate of the as-received aluminum was about 15.5 times higher than those of the 4 and 6-pass fabricated composites.

This study aimed to deposit multi-elemental coatings, including Ni-Co-Mo-W, Ni-Co-Cu-W and Ni-Co-Cu-Mo-W, with different configurational entropy from an aqueous bath by direct current electrodeposition. For this purpose, the effect of current density on the elemental composition was studied, and it was shown that the induced deposition of W was mainly controlled by Co, while the induced deposition of Mo was affected by both Ni and Co. In addition, Ni showed an activation deposition mechanism, while Mo suffered from concentration polarization for a prolonged electrodeposition process. All elements deposited homogeneously through the coatings' thickness except Cu showed some segregation. However, XRD spectra proved to have an amorphous structure for all coatings. Upon heat treatment, the crystallization of the coatings occurs, which results in an increase in hardness values from 5.6 to 11 GPa by increasing the heat treatment temperature up to 800 °C in the case of Ni-Co-Mo-W coating. The maximum hardness values were achieved at 500 °C in other coatings, and then a slight decrease was observed. Polarization results of the as-deposited coatings showed the potential for passivation of these coatings. However, due to the defects in the coatings, they were not completely protective towards the substrate. The results suggest that the presence of Cu had the main impact on the coating's properties since it decreased Co deposition, the hardness and the thermal stability of the coatings.

A simulation methodology has been developed and experimentally validated, including a simplified three-dimensional finite-element heat transfer model of the laser surface cladding/alloying process. Cladding/alloying of a nickel-based superalloy powder on grey cast iron substrate has been studied. By introducing and estimating a power scaling factor, it has been shown that the model is capable for prediction of the penetration depth into the substrate, heat-affected zone size and dilution ratio at various laser powers, based on a single laser cladding/alloying experiment to deliver the model input and data for comparison.

This paper aims to develop a proper and valid simulation model for electroplating complex geometries. Since many variables influence the quality of the deposited coating and its thickness distribution, it is challenging to conduct efficient research only through experiments. In contrast, simulation can be an efficient way to optimize the electroplating experiments. Despite its potential, simulation has seen limited commercial use in the electroplating industry due to its inherent complexity and difficulty in achieving accurate precision for intricate geometries. The present study addresses the aspects that can enhance the electroplating simulation's accuracy, which has been typically overlooked in the literature, such as the effect of current efficiency and its dependency on the current density, the input data for the electrode kinetics, the surface topology changes, and the differences between 2 and 3D simulations. The simulation model was validated by experimental results related to the coating thickness of Ni plating on a T-joint geometry. The results showed good agreement with the experimental ones, confirming the model's ability to precisely predict the coating thickness and distribution and promote its broader utilization in the industry. Finally, the developed model was used to determine the optimal current density regime for achieving uniform coating thickness distribution on a T-joint sample.

Understanding and evaluating the performance of different powder and substrate materials combined in the laser cladding/alloying layer is prioritised by process and material engineers to obtain high-quality durable surfaces. The surface quality is usually determined by the combination of various process parameters, such as laser power, powder feeding rate, and scanning speed, that result in different dilution ratios. Furthermore, process parameter calibration highly depends on the surface geometry and alignment of the deposited tracks. The application of simulation tools for the manufacturing process design tends to reduce experimental efforts. However, laser surface cladding and alloying represents a complex manufacturing process, where powder deposited on the surface of a material solidifies and forms an alloy with the substrate. Full-scale process simulation is often not feasible for parametric studies aiming at tuning the process parameters.  

The present work introduces an experimentally validated simulation methodology, including a simplified three-dimensional finite-element heat transfer model of the laser surface cladding/alloying process, Figure 1. Cladding/alloying of a nickel-based superalloy powder on the grey cast iron substrate has been studied. With the help of laser cladding experiments and measurements on cross-section images, it has been shown that the model is capable to predict the actual laser power to obtain the desired penetration depth into the substrate, heat-affected zone size and dilution ratio. It is shown by introducing a laser power scaling factor that the model input and comparison data can be obtained from a single cladding/alloying experiment. 

This study aimed to investigate the influence of process parameters on crack formation in laser alloying or cladding of grey cast iron. For this purpose, the effects of laser power and feeding rate of Ni-based alloying powders were examined. The microstructure and hardness of the coating and the interface of the coating with cast iron (bonding zone) were studied. The results showed that the dilution ratio is crucial in crack formation, explaining the challenges in achieving a defect-free laser alloying coating on cast iron. The higher dilution ratio of laser alloying resulted in higher dissolved carbon and bigger (Nb, Ti)C carbides formation than in laser cladding coatings. In this study, cracks appeared in the coating due to the combination of the high amount of carbide in the layer and a sharp hardness gradient at the interface with the cast iron substrate. An empirical relation was proposed for dilution ratio as a function of specific energy density, which combined the most critical process parameters on crack formation.

Commercially pure copper rod was successfully subjected to severe plastic deformation by applying the continuous equal channel angular pressing (ECAP-Conform) method at room temperature. Microstructural characterizations of copper rod samples at various stages of plastic deformation were carried out by optical microscopy and electron backscatter diffraction methods. X-ray diffractometry and Kernal average misorientation were used for dislocation density estimations. Microstructural evaluations revealed grain size change of 30 mm for the initial annealed copper rod to less than 5 mm and even 100 nm for severely deformed samples. Mechanical behaviors of samples after different deformation stages were characterized using tensile and hardness tests. The ultimate tensile strength of the severely deformed copper rod was increased threefold by ECAP-Conform while elongation halved in comparison to the initial annealed copper. Low-temperature annealing of severely plastic deformed samples led to bi-modal grain size distribution and lowering of strength accompanied by the increase of elongation. Tensile properties of severely deformed and then annealed copper samples showed around a 40% increase in both ultimate tensile strength and elongation in comparison to the initial annealed copper rod.