Effects of warm saddle forging deformation on the reduction of second-phase particles and control of the three-dimensional mechanical properties of 2219 aluminum alloy rings

Abstract

Severely segregated Al2Cu coarse second-phase particles (CSPPs) and uneven mechanical properties are the main problems in the manufacturing process of 2219 aluminum alloy large rings. A new method for the control of the three-dimensional mechanical properties (TDMPs) of the rings is proposed in the present study. The evolution law of the Al2Cu particles and the regulation mechanism of the TDMPs were investigated. The research revealed that optimizing the warm compression and rolling deformation can effectively reduce the quantity of CSPPs and regulate the TDMPs. With the increase of compression deformation (from 30% to 70%), the degree of the crushing and passivation of CSPPs was found to increase, the area fraction of the CSPPs decreased by 72.6%, and their roundness factor increased from 0.694 to 0.845; in the compression deformation process, high-density dislocations can effectively promote the crushing, dissolution and diffusion of Al2Cu particles, thereby enhancing the precipitation driving force of the strengthening phase during aging, resulting in a 99% increase in the quantity of the θ′ phase. When the compression deformation was 20% at 510 °C and 50% at 240 °C, the tensile strength, yield strength, and elongation of the ring in the radial direction were found to increase from 392 MPa, 287 MPa, and 6.4% to 468 MPa, 358 MPa, and 11.2%, respectively; moreover, the anisotropies of the three indicators of the rings were reduced by 32.6%, 54.0%, and 38.9%, respectively.