In this article, the effect of process parameters on the microstructure and mechanical properties of AW5083 aluminum alloy weld joints welded by a disk laser were studied. Butt welds were produced using 5087 (AlMg4.5MnZr) filler wire, with a diameter of 1.2 mm, and were protected from the ambient atmosphere by a mixture of argon and 30 vol.% of helium (Aluline He30). The widest weld joint (4.69 mm) and the highest tensile strength (309 MPa) were observed when a 30 L/min shielding gas flow rate was used. Conversely, the narrowest weld joint (4.15 mm) and the lowest tensile strength (160 MPa) were found when no shielding gas was used. The lowest average microhardness (55.4 HV0.1) was recorded when a 30 L/min shielding gas flow rate was used. The highest average microhardness (63.9 HV0.1) was observed when no shielding gas was used. In addition to the intermetallic compounds, β-Al₃Mg₂ and γ-Al₁₂Mg₁₇, in the inter-dendritic areas of the fusion zone (FZ), Al₄₉Mg₃₂, which has an irregular shape, was recorded. The application of the filler wire, which contains zirconium, resulted in grain refinement in the fusion zone. The protected weld joint was characterized by a ductile fracture in the base material (BM). A brittle fracture of the unshielded weld joint was caused by the presence of Al₂O₃ particles. The research results show that we achieved the optimal welding parameters, because no cracks and pores were present in the shielded weld metal (WM).

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).

Local plastic deformation in cutting zone during turning is affected by technological conditions of the processes. Therefore it is needful to know detail structure changes of plastic deformed material during machining. It is localised, asymmetric deformation which operates at very large strains and exceptionally high strain rates. Three areas of intensive local plastic deformation in cutting zone were observed: the primary area of plastic deformation in shear plane, the secondary area of plastic deformation caused by friction of chip to tool face and the tertiary area of plastic deformation caused by friction of tool to machined surface. Local strain in these three areas was estimated by measurement of deformation of grains on metallographic cut. The effect of grains boundaries self-orientation caused by grains deformation was evaluated using stereology. But the orientation is not the same as deformation and so a correlation between the grain deformation and grain orientation was used. The turning piece was made of CK45 (1.0503) carbon steel. The specimen of cutting zone was obtained by using internal stress method.