An analysis of void coalescence in AL 5052 alloy sheets annealed at different temperatures formed under different stress conditions

Abstract

In this paper the void growth, coalescence and fracture behavior of aluminium 5052 alloy are studied at different annealing temperature as a function of various void parameters, namely d-factor, δ d-factor, void area fraction ( V a) and L/ W ratio of the voids. The L/ W ratio of the oblate or prolate voids at fracture is correlated with the mechanical properties, microstructure, minor strain at fracture ( ɛ 2), Mohr's circle shear strains, stress, and strain triaxiality factors. The Lode factor ( θ) is determined and correlated with the stress triaxiality factor ( T), which is the ratio of mean stress ( σ m) to effective stress ( σ e). Void area fraction ( V a) is determined and correlated with the strain triaxiality factor ( T o). It is found that the sheets annealed at 350 °C, possesses better formability compared to the other annealing temperatures. This is due to its recrystallized grain structure, lower d-factor, greater void area fraction ( V a) and lower L/ W ratio of void, lesser stress triaxiality factor, accommodating more plastic deformation.