In situ study of micro-damage evolution in 2195 aluminum alloy

Abstract

2195 aluminum alloy has emerged as a highly valuable aerospace material due to its exceptional strength-to-weight ratio. However, its limited ductility and crack susceptibility during room-temperature forming restrict wider application. To elucidate the underlying damage mechanisms, this study employed multi-stage in situ tensile experiments combined with microscopic digital image correlation (micro-DIC) to quantitatively analyze the damage mechanisms and evolution of second-phase particles with varying characteristics. Additionally, a finite element model based on actual microstructure and deformation boundary conditions was developed, enabling precise simulation of the deformation process. The experimental results indicate particle size significantly affects the failure strain, while particle shape governs the damage mechanisms. The strain localization induced by the fracture of irregular and coarse particles promotes the formation of localized deformation bands, thereby activating the damage mechanism of particle debonding. Simulation further reveals that post-yield stress concentration and elevated stress triaxiality within irregular particles trigger damage initiation. Subsequent matrix regions near fractured particles exhibit increased stress triaxiality, accelerating matrix degradation. Beyond the ultimate tensile strength, the substantial increase in shear stress caused by interface debonding facilitates the coalescence of voids along the strain bands. These findings provide mechanistic insights into particle-induced damage processes and offer predictive guidelines for enhancing the room-temperature formability of 2xxx series aluminum alloys.