In-situ study of deformation and failure mechanics of Mg/Al laminates

• Strain localization occurs in Mg, while the Al exhibits more uniform deformation. • The Al layer shows higher void density compared to that of the Mg layer. • The local strain concentration in the Mg layer is caused by its low CRSS. • Strain incompatibility promotes crack initiation in Al and delays failure in Mg. Herein, Mg/Al laminates were fabricated via one-pass hard plate rolling with a 50% reduction at 535°C. The deformation mechanisms, strain partitioning, and fracture behavior were investigated via ex/in-situ characterization. The in-situ high-resolution digital image correlation (HR-DIC) shows that strain localization occurred preferentially in the Mg layer, while the Al layer exhibited more uniform deformation. In-situ X-ray computed tomography (XCT) tensile test reveals a higher void density in the Al layer than the Mg layer, with voids primarily concentrated near the interface. Stress analysis indicates that the Al layer experienced additional tensile stress transferred from Mg, while the compressive stress imposed by the Al layer suppressed void nucleation in the Mg layer. This strain incompatibility promoted crack initiation in Al while delaying failure in Mg. This work provides fundamental insights into the failure mechanics of Mg/Al laminated composites, offering a potential strategy for enhancing the mechanical performance of lightweight structural materials.