The aim of this work is to study joining Al 2024-T3 alloy plates with different welding procedures. Aluminum alloy AA 2024-T351 is especially used in the aerospace industry. Aluminum plates are welded by the TIG and MIG fusion welding process, as well as by the solid-state welding process, friction stir welding (FSW), which has recently become very important in aluminum and alloy welding. For welding AA2024-T35 with MIG and TIG fusion processes, the filler material ER 4043—AlSi5 was chosen because of reduced cracking. Different methods were used to evaluate the quality of the produced joints, including macro- and microstructure evaluation, in addition to hardness and tensile tests. The ultimate tensile strength (UTS) of the FSW sample was found to be 80% higher than that of MIG and TIG samples. The average hardness value of the weld zone of metal for the MIG- and TIG-produced AA2024-T3511 butt joints showed a significant decrease compared to the hardness of the base metal AA2024-T351 by 50%, while for FSW joints, in the nugget zone, the hardness is about 10% lower relative to the base metal AA2024-T3511.

Adhesive bonding has proven to be a reliable method of joining materials, and the development of new adhesives has made it possible to use bonding in a variety of applications. This article addresses the challenges of bonding metals such as the aluminum alloy EN AW-5754 and the stainless steel X5CrNi18-10. In this study, the effects of laser cleaning and texturing on the surface properties and strength of two bonded joints were investigated and compared with mechanical preparation (hand sanding with Scotch-Brite and P180 sandpaper). The bonded joints were tested with three different epoxy adhesives. During the tests, the adhesion properties of the bonded surface were determined by measuring the contact angle and assessing the wettability, the surface roughness parameters for the different surface preparations, and the mechanical properties (tensile lap-shear strength). Based on the strength test results, it was found that bonded joints made of stainless steel had 16% to 40% higher strength than aluminum alloys when using the same adhesive and surface preparation. Laser cleaning resulted in maximum shear strength of the aluminum alloy bond, while the most suitable surface preparation for both materials was preparation with P180 sandpaper for all adhesives.

Use of composite materials has seen significant growth, especially in the manufacture of lightweight structures and biomedical applications. One type of composite material is made up of polymer materials reinforced with glass fibres. PA6-GF reinforced with 25 % chopped glass fibres is a representative of this composite material group. The manufacturer recommends annealing as a heat treatment process after production. However, annealing requires additional equipment and time. This paper seeks to investigate the effect of non-annealed PA6 GF on the Charpy impact properties. Samples for Charpy impact property tests are defined according to BAS EN ISO 179-2:2021. The test specimens were printed on the FlashForge Creator 3 PRO printer, and the testing was performed on the AMSLER RPK300 device.

Adhesive bonding is a well-established technique for joining materials. This article deals with the challenges of bonding metals, such as aluminium alloy EN AW-5754. To improve the strength of bonded joints, suitable surface preparation prior to bonding is essential. In this work, the surface of the aluminium alloy using three different epoxy adhesives was subjected to two different methods of surface preparation, such as laser cleaning and sanding by hand with sandpaper. The adhesion properties of the bonded surface were determined by measuring the surface roughness parameters (Ra and Rz) for different surface preparations as well as the mechanical property (tensile lap-shear strength). It was found that the bond strength of the aluminium alloy changed depending on the surface preparation and adhesive used, indicating that using the same adhesive and material with different preparation methods can lead to significant variations in bond strength. Therefore, choosing an appropriate surface preparation method that is suitable for the parts to be bonded and their surface roughness is crucial as it increases the strength of the bonded joints.

The additive technologies such as 3D printing are an important part of all branches of industry, primarily due to the possibility of production parts with complex geometries. The aim of the research presented in this paper is the analyze of joining 3D printed polymer parts with adhesive. Furthermore, the aim of this research is to analyze the strength of lap adhesive joints under different loads. FDM technology, PLA materials and two-component epoxy adhesive were used to fabricate the testing specimens.

This paper aims to present the effects of the MIG welding on the mechanical properties of a buttwelded joint of dissimilar aluminium alloys 2024-T351 and AA 6082-T6. Aluminium alloy 6082 T6 is well weldable by classical fusion welding processes (MIG and TIG), while aluminium alloy 2024-T351 is almost non-weldable. For the welding of these two Al alloys, the MIG welding was used on an 8 mm thick sheet using filler material 4043A (AlSi5) and a mixture of argon and helium as a shielding gas. The influence of MIG welding on the obtained structure and mechanical properties of the welded joint was analyzed. The assessment of the mechanical properties of the welded joint of dissimilar Al alloys was performed by Vickers hardness testing, tensile and bending tests of the welded samples.

Multi-material design was developed as a modern design concept for lightweight structures (Lightweight design - LW) which aims to integrate different types of materials into one structure. The main problem when joining sheets made of different, i.e. dissimilar materials, primarily steel and aluminum alloys, are the different mechanical, physical and chemical properties of the materials being joined. Through this paper, the state of the art will be analyzed when it comes to modern technologies for joining steel and aluminum alloys sheets. The term "modern joining technique" refers to all innovative joining technologies that have been developed or have seen significant application in the last few years.

The modern concept of lightweight design (LW) requires the application of different materials in one structure (multi-material structures). The structure of different materials has a good perspective for application in the automotive and aerospace industries but only if it is possible to achieve a quality joint between different materials. The most used technology for joining different materials in the automotive industry is Resistance spot welding (RSW). Due to different mechanical, physical, and chemical properties, the joining of different materials by RSW technology does not provide a quality joint, and accordingly, alternative technologies for joining different materials have emerged. Resistance element welding (REW) was developed to enable joint of different materials. This paper presents the welding of AW 5754 H22 Al alloy (1.0 mm-thick) and DP500 steel (1.5 mm-thick) using novel REW. The peak load, absorption energy, microstructure, microhardness and fatigue strength of the REW joint has been investigated. The joint of the same materials has been done also using conventional RSW to compare some results. The results that will be presented in this paper show that that REW can achieve reliable joining of the two materials at relatively low welding currents compared to RSW. Using REW process with a significantly lower welding current, satisfactory mechanical characteristics of the weld joint can be achieved, so peak load is between 2300–2500 N, displacement is between 2.5–3 mm and the absorption energy is between 3.3–5.7 J. REW joints showed fatigue strength with the fatigue limit of 882 N.

In order to ensure a quality welded joint, and thus safe operation and high reliability of the welded part or structure achieved by friction stir welding, it is necessary to select the optimal welding parameters. The parameters of friction stir welding significantly affect the structure of the welded joint, and thus the mechanical properties of the welded joint. Investigation of the influence of friction stir welding parameters was performed on 6-mm thick plates of aluminum alloy AA2024 T351. The quality of the welded joint is predominantly influenced by the tool rotation speed n and the welding speed v. In this research, constant tool rotation speed was adopted n = 750 rpm, and the welding speed was varied (v = 73, 116 and 150 mm/min). By the visual method and radiographic examination, imperfections of the face and roots of the welded specimens were not found. This paper presents the performed experimental tests of the macro and microstructure of welded joints, followed by tests of micro hardness and fracture behavior of Friction Stir Welded AA2024-T351 joints. It can be concluded that the welding speed of v = 116 mm/min is favorable with regard to the fracture behavior of the analysed FSW-joint.