International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This study examines how thermal and mechanical effects influence hardness distribution in 4, 6, and 8 mm AA5754 aluminum plates welded using TIG with AC and DC currents. Vickers hardness (HV0.01) was measured alongside tensile tests to evaluate weld performance. Results show that AC welding produces higher but more variable hardness, while DC welding yields more stable profiles. Notably, thinner plates (4 mm) showed minimal hardness differences between current types due to faster cooling. Strain hardening increased hardness up to 125 HV and reduced variation. The extent of hardness stabilization and heat-affected zone size depended on plate thickness. Although current type influenced hardness distribution, it had little effect on fracture toughness.

This article analysеs the Specific Absorption Rate (SAR) and outlines the thermal effect in depth of the human head. SAR is the most important dosimetric value when the human body is irradiated with signals in the radio frequency range. For this purpose, a computer model is created using COMSOL Multiphysics software, taking into account the specific characteristics of the human head and the parameters of a working smartphone. This model is suitable for studying the effects of radio waves on humans

Grain boundary wetting process takes place during the contact of solid metal phase with the metal melt. The liquid bismuth network formation along grain boundaries (GB) connected with wetting process was investigated in copper polycrystalline samples. The endothermic thermal effect in the temperature range close to complete GBs wetting transition temperature for Cu-Bi system was observed. Thermal effect size of GB wetting per mol of copper passed into bismuth melt during process of forming wetting GB channels was characterized as 21-23 kJ/mol.