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This study aims to demonstrate the capability of the digital image correlation (DIC) technique for evaluating full-field residual stresses in wire and arc-additive-manufactured (WAAM) components. Investigations were carried out on WAAM steel parts (wall deposited on a substrate) with two different wall heights: 24 mm and 48 mm. Mild steel solid wire AWS ER70S-6 was used to print WAAM walls on substrates that were rigidly clamped to H-profiles. DIC was used to monitor the bending deformation of WAAM parts during unclamping from the H-profiles, and residual stresses were calculated from the strain field captured during unclamping. Residual stresses determined from the proposed DIC-based method were verified with an analytical model and validated by the results from established residual stress measurement techniques, i.e., the contour method and X-ray diffraction.

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The demand for joining dissimilar metals has exponentially increased due to the global concerns about climate change, especially for electric vehicles in the automotive industry. Ultrasonic welding (USW) surges as a very promising technique to join dissimilar metals, providing strength and electric conductivity, in addition to avoid metallurgical defects, such as the formation of intermetallic compounds, brittle phases and porosities. However, USW is a very sensitive process, which depends on many parameters. This work evaluates the impact of the process parameters on the quality of ultrasonic spot welds between copper and aluminium plates. The weld quality is assessed based on the tensile strength of the joints and metallographic examination of the weld cross-sections. Furthermore, the welding energy is examined for the different welding conditions. This is done to evaluate the influence of each parameter on the heat input resulting from friction at the weld interface and on the weld quality. From the obtained results, it was possible to optimise parameters to achieve satisfactory weld quality in 1.0 mm thick Al–Cu plate joints in terms of mechanical and metallurgical properties.

Ultrasonic welding is increasingly used in industry. In this paper, the influence of ultrasonic welding parameters (USW) on the joint strength and quality was analysed. The properties of the USW joints depend on many factors. The work focuses on the influence of the technological parameters and the surface properties of welded EN Cu-ETP copper sheets with a thickness of 1 mm. The impact of the process parameters, such as welding time, pressure, vibration amplitude and the surface roughness on the lap shear strength and the metallographic weld properties was analysed. The welding energy for each variant was also determined. The research was conducted on the basis of a full factorial design of experiments. The optimal process parameters were determined to obtain high-quality joints in terms of strength and weld quality. Based on the presented experimental study, it was demonstrated that the ultrasonic vibration amplitude has the greatest impact on the joint strength. A surface preparation with acetone resulted in the highest tensile strength and welding energy and, making any additional surface treatment prior to welding unnecessary.

Hybrid laser-arc welding (HLAW) is regarded as a promising joining process, since it can compensate disadvantages from laser autogenous welding and arc welding by uniting both techniques into a single melt pool. Such a process can achieve relative high quality metallurgical bonding, high speed, and low deformation. However, the process is considered complex and of difficult parametrization, as the four states of matter come to coexist in the same space and as the union of two processes generates interactions that are still not well understood [C. Churiaque, M. Chludzinski, M. Porrua-Lara, A. Dominguez-Abecia, F. Abad-Fraga, and J. Maria Sánchez-Amaya, “Laser hybrid welding of large thickness naval steel,” Metals J. 9, 100 (2019); G. Casalino, Hybrid Laser Welding: A Review, DAAAM International Scientific Book (DAAAM International, Vienna, 2010), Chap. 38, pp. 413–430; and B. Ribic, T. A. Palmer, and T. DebRoy, “Problems and issues in laser-arc hybrid welding,” Int. Mater. Rev. 54, 223–244 (2009)]. One of HLAW’s main variations is studied and evaluated in this work, the hybrid laser-Tungsten Inert Gas (TIG) welding process. In this process, the interaction between the arc and the laser-induced plume is dependent on the shielding gas flow, arc welding current and voltage, laser beam characteristics, and the geometric relations between electrode, laser incidence position, and workpiece. Here, in order to further analyze the influence of the laser power on arc behavior during the hybrid process, tests were performed by varying the TIG current and laser power parameters from 60 to 100 A with increments of 20 A and 0 to 2500 W with increments of 500 W, respectively. From an arc’s voltage monitoring, one can analyze the influence of the interaction between the arc’s plasma and the plume induced by the laser. It was observed that the perturbation generated by the laser beam is directly proportional to its power, as there is an increase in the average voltage and the perturbance amplitude as a function of the applied laser power. The analysis presented over the dynamic aspect of the hybrid welding process and the influence of the laser beam on the arc contribute to the laser-TIG welding consolidation within the academic and industrial scenario.

Problems related to component wear are one of the biggest challenges faced by industrial sectors such as agriculture, mining, and oil and gas. Coating application has been a good alternative to mitigate these problems. Ni-Cr-B-Si alloys are recognized for their abrasion and adhesion resistance properties. In this context, a comparison between the mechanical wear of Ni-Cr-B-Si 1545-00 deposited via laser metal deposition is performed in two setups. The goal was to study the effect of the cladding direction in the coating wear resistance. The coated samples were prepared according to the dimensions required by ASTM G65, a dry sand/rubber wheel test standard. Using procedure A of ASTM G65, pauses were done every 5 min for volumetric loss measurement. In parallel, the coating cross section was metallographically prepared and evaluated via optical microscopy and scanning electron microscopy (SEM)-x-ray dispersive energy spectroscopy (EDX). Vickers microhardness profile was also measured, and its value reached 580 HV1. Worn surfaces were evaluated via SEM-EDX; however, this time the microscopy technique was used to characterize wear mechanisms. In the microhardness profile analysis, the average was much lower in the diluted region and the heat-affected zone. As to the tribological test results, volumetric loss increased in proportion to the test time. In the first setup, coating presented an average volumetric loss of 37% higher than the second setup. This result can be attributed to the dry sand/rubber wheel test direction. This work's outcome indicates that a coated component's lifetime may be improved when attention is given to coating orientation and component preferential mechanical wear direction.

Ultrasonic welding (USW) is a solid-state welding process based on the application of high frequency vibration energy to the workpiece to produce the internal friction between the faying surface and the local heat generation required to promote the joining. The short welding time and the low heat input, the absence of fumes, sparks or flames, and the automation capacity make it particularly interesting for several fields, such as electrical/electronic, automotive, aerospace, appliance, and medical products industries. The main problems that those industries have to face are related to the poor weld quality due the improper selection of weld parameters. In the present work, 0.3 mm thick copper sheets were joined by USW varying the welding time, pressure, and vibration amplitude. The influence of the process variables on the characteristics of the joints and weld strength is investigated by using the analysis of variance. The results of the present work indicate that welding time is the main factor affecting the energy absorbed during the welding, followed by the pressure and amplitude. The shear strength, on the other hand, resulted mostly influenced by the amplitude, while the other parameters have a limited effect. Regardless the welding configuration adopted, most welds registered a failure load higher than the base material pointing out the feasibility of the USW process to join copper sheets.