Elevated-temperature mechanical properties and thermal stability of Al-Cu-Mg-Ag heat-resistant alloy

Abstract

The elevated-temperature mechanical properties and thermal stability of Al-Cu-Mg-Ag heat-resistant alloy were studied by tensile test, transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. The results show that with the increase of Ag content, the tensile strength and yield strength increase, which is attributed to the increase of the precipitations number and the decrease of the size. The same conclusions are drawn in the study of increasing Mg content. The alloy possesses excellent thermal stability. At 100–150 °C, the strength of the under-aged alloy increases at the initial stage, and after reaching the peak strength, it remains the same. The secondary precipitation of the under-aged alloy occurs in the process of exposure at 150°C, and it distributes diffusely after thermal exposed for 20 h. Then, the tensile strength decreases gradually with increasing the thermal exposure time at 200–250 °C. The strength of the peak-aged alloy decreases gradually, and the precipitation grows up, but the number decreases gradually with prolonging the exposure time at 100–250 °C. The strength of two kinds of alloys decreases with elevating of exposure temperature.

Keywords

evaluated-temperature mechanical properties / thermal stability / Al-Cu-Mg-Ag alloy

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