Effect of ion irradiation on structural state and mechanical properties of naturally-aged hot-pressed D16 (Al-Cu-Mg) alloy profiles

The effect of irradiation with 20 keV argon ions on the mechanical properties, structure, and phase composition of quenched and then naturally aged, hot-pressed profiles (6 mm thick) from the D16 alloy of the Al-Cu-Mg system has been studied. It was found that short-term irradiation with Ar+ ions (E = 20 keV, j = 200 μA/cm², F = 1×10¹⁶ cm^-2, irradiation time 8 s) leads to transformation of the microstructure and phase composition of the alloy. The coarsening of the initial subgrain structure occurs near the sample surface. Both in the surface layer and at a distance of ∼ 150 μm from it, partial dissolution and fragmentation of complex intermetallic compounds of crystallization origin located along grain boundaries are observed, as well as a decrease in the size and change in the morphology of Al₆(Fe, Mn) intermetallic compounds of crystallization origin are observed too: the distribution density of lamellar precipitations decreases, and equiaxial precipitations disappear. Under the influence of irradiation, the decomposition of the supersaturated solid solution is activated with the formation of a more stable phase S'. As a result of ion-beam treatment in this mode, the plasticity of the alloy increases while maintaining the strength properties.