Effects of deformation temperature on second-phase particles and mechanical properties of multidirectionally-forged 2A14 aluminum alloy

Abstract

Age-hardenable 2A14 aluminum alloy was subjected to multidirectional forging (MDF) at different temperatures (380, 430, 480 °C) and then treated with solid-solution and T6 aging. The effect of the MDF temperature on the evolution and distribution of second-phase particles and mechanical properties was examined. The results showed that many coarse particles adopted a network distribution when the sample was MD-forged at a lower temperature. This induced large stress concentrations that acted as crack initiation sites, resulting in a decrease in the mechanical properties. Upon increasing the MDF temperature, the number of coarse particles decreased and became more spherical. Correspondingly, the solubility of solute atoms and the atomic diffusion rate increased, which enhanced the precipitation ability, density, and uniformity of the precipitated phases. Thus, upon increasing the MDF temperature, the mechanical properties of the 2A14 alloy were enhanced, while the uniformity was improved in all three directions. The best mechanical properties in all three directions were obtained at an MD-forging temperature of 480 °C, with room-temperature UTS values of 484 MPa, 450 MPa, and 448 MPa; YS values of 365 MPa, 357 MPa, and 356 MPa; and EL values of 11.0%, 10.5%, and 8.0%.