Effect of Microstructure on Mechanical Properties of 2519A Aluminum Alloy in Thickness Direction

2519A aluminum alloy thick plate is a promising structural material in the field of military industries, owing to its low density, high tensile strength and excellent ballistic performance. However, the nonuniformly distributed microstructure along the thickness direction of this alloy leads to delamination cracks, which restrict its further application in light armor fields. In order to understand the mechanism of delamination cracking along the thickness direction, the effect of the microstructure on the mechanical properties of 2519A aluminum alloy in the thickness direction was investigated. The results show that the elongation and critical stress intensity factor values (Δ<i>K_cr</i>) of the alloy in the thickness direction are 45.8% and 44.1% lower than the values in the rolling direction, respectively. The low mechanical properties of the alloy may be due to the short distance between the second phase, the weak binding force of grain boundaries and the disharmonious deformation caused by the inhomogeneous distribution of the microstructure. This study provides a basis for improving the mechanical properties and delamination cracking of the alloy along the thickness direction.