The results disclosed that both the microstructure and mechanical properties of AA7075-T6 laser welds are considerably influenced by the heat input. In comparison with high heat input (arc welding), a smaller weld fusion zone with a finer dendrite arm spacing, limited loss of alloying elements, less intergranular segregation, and reduced residual tensile stress was obtained using low heat input. This resulted in a lower tendency of porosity and hot cracking, which improved the welded metal’s soundness. Subsequently, higher hardness as well as higher tensile strength for the welded joint was obtained with lower heat input. A welded joint with better mechanical properties and less mechanical discrepancy is important for better productivity. The implemented high-power fiber laser has enabled the production of a low heat input welded joint using a high welding speed, which is of considerable importance for minimizing not only the fusion zone size but also the deterioration of its properties. In other words, high-power fiber laser welding is a viable solution for recovering the mechanical properties of the high-strength AA 7075-T6 welds. These results are encouraging to build upon for further improvement of the mechanical properties to be comparable with the base metal.

The article presents the results of a research of the process of laser hardening of steel 14Cr17Ni2 (AISI 431) by radiation of a high-power fiber laser LS-16. Assessment of the theoretically possible maximum depth in laser processing without additional beam transformations, the use of additional coatings and devices were shown. The results of experiments on increasing the depth of the hardened layer during laser processing by using scanning of the laser beam and optimally selected mode parameters without scanning are demonstrated. The influence of the number of passes on the depth of the hardened layer is investigated. The microstructure of hardened samples was studied and quantitative estimation of structural components was carried out. The microhardness of hardened samples at different modes of laser hardening was measured.

The technology of layer-by-layer deposition is the most relevant for the manufacture and repair of products, due to the least time and resource costs compared to traditional manufacturing technologies. In the same time, application of wire instead of powder, allows to reduce consumption of filler material and increase production efficiency. In this regard, research was carried out on the influence of the parameters on the wire deposition process to form thin walls of copper-nickel alloys using a laser and arc method. For the wire deposition of copper-nickel walls, CuNi6 wire was used. Experimental work was carried out on the technological complex, based on the fiber laser power up to 16 kW and the arc source for MIG welding. The report presents samples of deposition walls, investigated alloys obtained for both deposition methods at various technological parameters. Metallographic studies of the samples were performed, microhardness was measured, and a comparative analysis of laser and arc deposition methods.

BACKGROUND: Studies of laser welding of titanium and aluminum is important for development of new materials and technologies, which in turn may improve the performance of end products in various industries, including automotive, aviation, and shipbuilding. However, laser welding of these materials is a complicated process due to differences in their physical and chemical properties. The study included a structural analysis of a welded joint of titanium and aluminum alloys and an analysis of its mechanical properties. The processing included welding in different modes. AIM: To analyze the structure of a welded joint made by laser welding of VT6 titanium alloy with 1545 aluminum alloy. METHODS: In this study, VT6 titanium alloy and 1545 aluminum alloy were used as the main welded materials. Rechflot arc augmented laser welding system and 3200 × 6000 mm workpieces were used for welding. RESULTS: The study identified key aspects affecting the mechanical properties and reliability of joints. Analysis of the resulting microstructures showed that laser welding allows to achieve a high degree of uniformity and density of the weld; however, it is required to consider the effect of thermal conditions and weld geometry on intermetallic joints. CONCLUSION: Formation of specific phases in the welding area requires further study to improve welding technology and the performance of joints. This study confirms that laser welding can be used to join Ti-Al systems, unveiling new possibilities to produce lightweight and high-strength structures in the aviation and space industries. Thus, to achieve higher strength and durability of joints, it is required to continue a deep analysis of the influence of various factors on welding processes, including the selection of suitable additives and processing conditions.