Rapidly improving the mechanical properties of Al-Li alloy via electropulsing rapid heating

Abstract

This study investigated the application of electropulsing pulse rapid heating (ERH) technology for the aging strengthening of Al-Li alloys, aiming to address the high energy consumption and low efficiency associated with traditional furnace heating (FH) methods. The experimental results demonstrated that ERH significantly reduced the time required to reach the target temperature, decreasing it from 2430 s to 155 s compared to conventional FH. A key finding was the identification of a current density threshold of 36 A/mm², at which the yield strength of the Al-Li alloy increased rapidly, peaking at approximately 433 MPa within 483 s. Above this threshold, a decrease in the mechanical properties of the alloy was observed. ERH effectively promoted recrystallization and reduced texture intensity in the Al-Li alloys. However, excessive current density led to the formation of the $S^{\prime }$ phase (Al₂CuMg) at grain boundaries, which significantly reduced the mechanical properties of the alloy. Furthermore, excessive current density reduced the proportion of the T₁ phase (Al₂CuLi), which significantly degraded the mechanical properties of the alloy. Compared to FH, ERH reduces energy consumption by 22 times and heating time by 15.7 times. This study presented an energy-efficient processing method for enhancing the properties of high-strength aluminum alloys, particularly for aerospace applications.