激光增材制造铝锂合金的热处理组织及T_B相析出

The Al-Li alloys are fabricated by the laser additive manufacturing technique, and the microstructures of the as-deposited Al-Li alloys are analyzed. The processing parameters for double-stage homogenization annealing and solution heat treatment are optimized, and the T_B phase precipitation behavior is explored. The results show that, after the double-stage homogenization annealing and solution heat treatment, the amount of copper-rich phase with a low melting point precipitated on the grain boundary and within grains is reduced, and thus the uniformity of Al-Li alloy compositions is improved. The amount of the precipitated T_B phase reaches the maximum at an aging temperature of 400℃, and with the further increment of the aging temperature, the amount of T_B phase gradually decreases. In addition, the micro-hardness decreases first and then increases with the increase of the aging temperature.