Study of thermal properties of the aluminium EN AW 2024-T3 alloy

Abstract

The thermal properties of the aluminum EN AW-2024 alloy (duralumin) delivered in the T3 condition (solution annealed, quenched, cold-deformed, and naturally aged) were experimentally investigated using differential thermal analysis (DTA), differential scanning calorimetry (DSC), and light flash apparatus (LFA) for thermal diffusivity and thermal conductivity evaluation. The microstructure of the alloy in the initial state and after heating to 400 ◦ C was investigated by scanning electron microscope (SEM) and energy-dispersive spectroscopy. The presence of an exothermic thermal effect in the temperature range from 230 to 283 ◦ C during the first heating of the examined sample was determined by the results of DTA/DSC analysis. The thermal diffusivity of the investigated alloy was measured in the temperature range from 25 to 400 ◦ C using three heating runs. During the first heating, the thermal diffusivity of the investigated alloy increased with an increase in temperature up to approximately 300 ◦ C, after which it decreased. During the second and third heating, it was observed that the measured thermal diffusivity values at temperatures lower than 300 ◦ C were significantly higher than during the first heating, and the thermal diffusivity gradually decreased with increasing temperature in the entire investigated temperature range. Experimentally determined thermal diffusivity and density, as well as calculated specific heat capacity data, were used to determine the thermal conductivity of the studied alloy in the temperature interval from 25 to 400 ◦ C. The obtained results indicate that initial heating to a temperature above 300 ◦ C causes a significant increase in the values of the thermal diffusivity and thermal conductivity of the investigated 2024-T3 alloy.