Commercially pure titanium Ti Grade 2, 2 mm in thickness, was welded to 2 mm thick nickel alloy 201 with electron beam welding. Various welding parameters were used to create the butt-welded joints. The innovation herein consists of welding two dissimilar metals that are declared non-weldable. The welding current used for electron beam welding was 40–70 mA and welding speeds were 20–50 mm/s. In this experiment, we tested two offsets of the electron beam, which were 100–300 μm to the nickel side and 200 μm to the titanium side. It was observed that the offset of the beam had no effect on the weld joint’s strength. The samples were subjected to a visual test in which longitudinal and transverse cracks were recorded along the whole weld. Only four samples retained the integrity of the joint. Microstructures of the weld joints were examined by scanning confocal and scanning electron microscopy. Energy dispersive spectroscopy (EDS) analysis confirmed the phase constitution inside the weld regions and the fusion interfaces. Tensile strength and microhardness tests were used to evaluate the mechanical parameters of the Ti/Ni welded joint. The results showed that cracking of brittle Ni–Ti intermetallic phases in electron beam welded joints occurred. The microstructure in the fusion zone’s center part was primarily NiTi and Ti₂Ni. No clear correlation was found between heat input or welding parameters—welding current and welding speed—and tensile strength. The strain–tensile strength curve resulted in brittle fracturing. The hardness of the weld zone was five times higher than that of the base metal and heat-affected zone. The amount of heat input into the welded metal is as critical as the large asymmetry in heat transport that controls the process of solidification from each side of the base metal.

The influence of laser beam welding parameters (power, welding rate, focusing, head oscillation, shielding gas) on the microstructure, mechanical properties and corrosion resistance of the super-duplex stainless steel SAF 2507 was studied in this paper. The presented results clearly report the effects of welding parameter changes on the character of the steel’s microstructure. The presence of secondary phase M₂N in weld metals has an important influence on their mechanical properties. Optimal mechanical properties, an acceptable ferrite/austenite ratio, and the minimum content of M₂N nitride required in the weld metal were acquired in the case the following application: 1100 W power, welding speed of 10 mm/s, focusing of 4 mm, and pure nitrogen shielding gas (20 L/min).

The paper deals with the welding of AW 2099-T83 aluminium lithium alloy being used for construction of lower wing stringers. The thickness of AW 2099-T83 aluminium lithium alloy was 25.4 mm. Electron beam welding with the accelerating voltage of 55 kV was used for production of welded joints. Welded joints were inspected by computer tomography, macroscopic and microscopic analysis, tensile strength test and microhardness measurement. Welded joints exhibited good weld joint formation, typical to electron beam welding. Weld metal was structure was dendritic formed by α solid solution. Decrease of microhardness was observed mainly in the centre of weld metal due to dissolution of precipitates. The fracture occurred in the weld metal during tensile strength test. Further research will focus on post-heat treatment of welded joints in order to improve mechanical properties of weld metal.