Complex investigation of the mechanical properties and structural-phase composition of high-strength laser welding connections of the aluminum alloy 1420

The paper presents a series of experimental works for the optimization of the thermal post-treatment process (quenching and artificial ageing) of the laser welding joints of aluminum-lithium alloy 1420 (the system Al-Mg-Li) by the temperature and time characteristics, in order to find the breaking stress, yield limit and ultimate tensile strain approaching to the respective characteristics of the main alloy, or equal to them. Low-cycle tests have been done with the thermally-treated welding joints for the pulsing stretching at various loading amplitudes at the temperatures of –60, +20, +85°С. The surface structure of ruptured welding joints with and without thermal treatment has been studied after low cycle tests at various loading amplitudes at the increased and decreased temperatures.