Damage mechanisms of 2195-O aluminum alloy sheet induced by microstructural evolution during tensile deformation at different temperatures

Abstract

The 2195 aluminum alloy is limited in aerospace structural components due to its poor formability at room temperature (RT) and narrow range of working parameters at hot deformation, which prompted considerable interest in understanding the microscopic damage mechanisms at different temperatures. This work focuses on the interaction between the second-phase particles and the matrix, as well as their evolving relationship to investigate the damage mechanisms of the 2195-O alloy. Particular attention was given to the nucleation mechanisms that trigger damage. SEM, BSE, and EBSD methods were employed to characterize the evolution of the microstructure during tensile tests ranging from RT to 450 °C. The results indicate that nucleation mechanisms exhibit temperature-dependent variations: At RT, a high area fraction of particles and inadequate coordination with matrix deformation lead to stress concentration on the particles, and particle fracture is the primary nucleation mechanism. Meanwhile, voids nucleate at the particle-matrix interface at 300–450 °C, where localized strain concentration is induced by differential deformation between particles and the matrix. Moreover, matrix cracking occurs at 450 °C due to a reduction in the quantity of particles and grain coarsening. Matrix-cracks tend to expand and aggregate, leading to decreased elongation at 450 °C.