Structural and Phase Changes in Al–Cu–Mg Alloy Plates in a Corrosive Medium during Operational Heating

The structure, phase composition, and mechanical and corrosion properties of plates made of a structural aluminum Al–Cu–Mg alloy are studied in its various states. The results obtained are compared with the properties of its commercial analog (AK4-1 alloy). The alloy under study is found to surpass its analog in strength properties at room and elevated (up to 175°C) temperatures by 9–12%. The impact toughness KCU of the Al–Cu–Mg alloy is twofold that of the AK4-1 alloy. The increase in the strength and corrosion properties of the alloy after operational heating is shown to be explained by the phase composition and morphology of intermetallic phases, including transition-metal phases, which form in the surface layers of samples in small quantities.