Precipitation behaviour in AlMgZnCuAg crossover alloy with coarse and ultrafine grains

Crossover aluminium alloys have recently been introduced as a new class of coarse-grained age-hardenable alloys. Here, we study the evolution of precipitation of the T-phase - M g(32)( Zn ,Al )(49) -phase - in a 5xxx/7xxx crossover alloy with coarse- and ultrafined microstructures. Both alloys were examined using differential scanning calorimetry, X-ray diffraction and in situ transmission electron microscopy. The ultrafine-grained alloy revealed significant different and accelerated precipitation behaviour due to grain boundaries acting as fast diffusion paths. Additionally, the ultrafine-grained alloy revealed high resistance to grain growth upon heating, an effect primarily attributed to inter-granular precipitation synergistically with trans-granular precipitation of T-phase.

Automated summary

This study investigates the precipitation behavior of the T-phase in crossover aluminium alloys, revealing that the ultrafine-grained alloy exhibits different and accelerated precipitation behavior compared to the coarse-grained alloy. Moreover, the ultrafine-grained alloy shows high resistance to grain growth during heating, primarily attributed to the synergistic effect of inter-granular and trans-granular precipitation of T-phase.