Mechanical Behavior and Fracture Mechanism of 2219 Aluminum Alloy with Different Heat Treatment Conditions Under Dynamic Loading

In this work, the mechanical response and fracture mechanism of 2219 aluminum alloy with different heat treatment conditions under dynamic loading were studied by split Hopkinson tension bar experiment. The results show that the tensile strength and strain rate sensitivity of 2219-T6 and 2219-T4 increase with the increase of strain rate, while that of 2219-O increases first and then decreases. And the strain rate sensitivity and strain hardening rate of 2219 aluminum alloy decrease with the increase of strain. Under the dynamic loading conditions, the material forms the partial dissociation morphology and the morphology of the second phase particle break under the higher stress concentration degree. And at higher strain rate (>= 650 s(-1)), with the increase of strain rate, the stress concentration degree becomes higher, and the proportion of dissociation morphology becomes larger. At the same time, because the material can still undergo a certain amount of deformation at the same time of crack propagation, the material as a whole has a higher forming limit under the higher strain rate (>= 650 s(-1)). It also leads to the formation of fracture morphology with low plasticity under the action of higher work hardening.