The paper presents the results of comparative tests of the fatigue properties conducted on two non-ferrous alloys designated as Al 6082 and

Al 7075 which, due to the satisfactory functional characteristics, are widely used as engineering materials. The fatigue tests were carried

out using a proprietary, modified low cycle test (MLCF). Particular attention was paid to the fatigue strength exponent b and fatigue

ductility exponent c. Based on the tests carried out, the results comprised within the range defined by the literature were obtained. These

results prove a satisfactory sensitivity of the method applied, its efficiency, the possibility of conducting tests in a fully economical way

and above all the reliability of the obtained results of the measurements. Thus, the thesis has been justified that the modified low cycle

fatigue test (MLCF) can be recommended as a tool used in the development of alloy characteristics within the range of low-cycle variable

loads

The article presents the analysis of properties of the high-strength AlZnMgCu (abbr AlZn) aluminium alloy and estimates possibilities of

its application for responsible structures with reduced weight as an alternative to iron alloy castings. The aim of the conducted studies was

to develop and select the best heat treatment regime for a 7xx casting alloy based on high-strength materials for plastic working from the

7xxx series. For analysis, wrought AlZnMgCu alloy (7075) was selected. Its potential of the estimated as-cast mechanical properties

indicates a broad spectrum of possible applications for automotive parts and in the armaments industry. The resulting tensile and fatigue

properties support the thesis adopted, while the design works further confirm these assumptions.

In this study, the mechanical tests were carried out on ductile iron of EN-GJS-600-3 grade and on grey cast iron of EN-GJL-250 grade. The fatigue life was evaluated in a modified low-cycle fatigue test (MLCF), which enables the determination of parameters resulting from the Manson-Coffin-Morrow relationship. The qualitative and quantitative metallographic studies conducted by light microscopy on selected samples of ductile iron with spheroidal graphite and grey cast iron with lamellar graphite (showing only small variations in mechanical properties,) confirmed also small variations in the geometrical parameters of graphite related with its content and morphological features.

This study discloses the characteristic features of the modified low-cycle fatigue test used for the determination of the mechanical

properties of two types of cast iron, i.e. EN-GJL-250 and EN-GJS-600-3. For selected materials, metallographic studies were also

conducted in the range of light microscopy and scanning microscopy.

The paper presents the possibility of using FSW technology for joining elements of a landing gear beam of the M28 aircraft. The FSW process was performed on a 4-axis numerical machine under industrial conditions. However, before welding was carried out under industrial conditions, preliminary experimental tests were carried out under laboratory conditions. Preliminary research was carried out for AA2024-T3 aluminum sheets of 1 mm and 3 mm in thickness, joined in a lap configuration. The influence of technological and geometric parameters of the process on the quality and strength of the weld was examined. Sheet metal arrangement was analyzed. Tests were carried out for two configurations. The first of which with 1 mm sheet on the top and 3 mm sheet on the bottom and in reverse order. It has been shown that setting a thicker plate on the top gives a 40% better strength. The microhardness and microstructure of the weld were tested. During the laboratory tests, low-cycle fatigue tests of the FSW lap joint were performed. It has been shown that the FSW method can be an alternative to the riveting process in the production of aviation structure elements.

The paper presents the results of research work on linear FSW (Friction Stir Welding) joining aluminum alloys AA2024-T3 of 0.5 mm in thickness. The study was conducted on properly adapted numerical controlled 3 axis milling machine using a ceramic tool and special designed fastening device. The tool dimensions have been estimated according to the algorithm shown in the literature [4]. All joints were made of end-to end (butt) configuration under different welding speed. The rotational speed of the tool and tool offset was constant. The effect of selected technological parameters on the quality of the joint was analyzed. Produced butt joint have been subjected to a static tensile testing to identify mechanical features of the materials of joints compared to parent materials. Measurements of micro hardness HV in the plastically formed stir zone of joint and in the parent material have been carried out. Axial and radial welding forces in the joining region were recorded during the tests and their dependency from the welding parameters was studied. Based on the results of strength tests the efficiency of joints for sheets of 0.5 mm in thicknesses oscillated up to 96% compared to the parent material. It has been found that for given parameters the correct, free of defects joints were obtained. The paper also presents the results of low-cycle fatigue tests of obtained FSW joints. The use of a ceramic tool in the FSW process allows to obtain welds with higher strength than conventional tools. The results suggests that FSW can be potentially applied to joining aluminum alloys.