Second phase particles and mechanical properties of 2219 aluminum alloys processed by an improved ring manufacturing process

Abstract

2219 Al alloy has been used to manufacture the launch vehicle storage tank transition ring, but the large ring obtained in conventional manufacturing processes still suffers from severely agglomerated coarse second phase particles and poor mechanical properties. An improved process (forging at 510 °C with 20% deformation and at 240 °C with 50% deformation, then rolling at 240 °C with 30% deformation, followed by solid solution at 538 °C for 4 h and T8 treatment) for 2219 Al alloy large ring manufacturing was proposed, and the corresponding simulation tests were carried out. The evolution of Al2Cu second phase particles and the mechanical properties of the produced workpieces were investigated. The results showed that the degree of crushing, dissolution, and precipitation of Al2Cu particles were significantly improved in the improved process, and the area fractions of Al2Cu coarse second phase particles after saddle forging and rolling were significantly reduced, leading to 2.4 times increase in area fraction of the θ′ phase after T8 treatment. More homogeneous slip occurred during the tensile testing process and intergranular fracture was the main fracture mechanism. The tensile strength σb, yield strength σs, and elongation δ in the radial direction of the 2219 workpieces were increased to 491 MPa, 388 MPa, and 13.1%, where were increases of 11%, 14%, and 68%, respectively. The uniformity in σb, σs, and δ of the 2219 workpieces increased by 57%, 38%, and 64%, respectively.