Exploring short crack behaviour and fracture transition in 5052 aluminium alloy

• Investigates crack-length dependency in 5052 aluminium alloy. • Reveals crack propagation on transgranular cleavage planes. • SIFs derived from the local displacement field show the transition from microstructurally sensitive crack to macro-crack. • Crack growth influenced by double-slip mechanisms. • DIC-derived SIFs capture real-time changes at the crack tip. This study, employing in-situ scanning electron microscopy, electron backscatter diffraction, and digital image correlation, investigates the crack-length dependency of the quasi-brittle to ductile transition in 5052 aluminium alloy. A compact tension sample with {110} texture was examined, revealing crack propagation on ( 11 1 ¯ ) and ( 1 ¯ 11 ) transgranular cleavage planes and non-coherent paths under low-stress intensity factors (SIFs), with a maximum of 7.72 ± 0.09 MPa.m 0.5 compared to the typical K I C of 25 MPa.m 0.5 . Crack growth was influenced by double-slip mechanisms and significant resistance at Σ33 grain boundaries. After crack arrest, SIFs derived from the local displacement field revealed a transition from microstructure-sensitive to nominal load-driven crack growth conditions.