激光增材制造铝锂合金的热处理组织及T_B相析出

Heat Treatment Microstructures and T_B Phase Precipitation of Laser Additive Manufactured Al-Li Alloys

采用激光增材制造技术制备了铝锂合金,分析了沉积态铝锂合金的显微组织,优化得到了沉积态铝锂合金的双级均匀化退火和固溶热处理工艺参数,并探讨了TB相的时效析出行为。结果表明,经过双级均匀化退火及固溶热处理后,铝锂合金晶界和晶内析出的低熔点富铜相数量减少,铝锂合金的成分均匀性得到提高。当时效温度为400℃时,铝锂合金中析出的TB相数量达到最大;随着时效温度的继续升高,TB相数量逐渐减少。铝锂合金的显微硬度随着TB相含量的增加先减小后增大。

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 TBphase 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 TB phase reaches the maximum at an aging temperature of 400 ℃,and with the further increment of the aging temperature,the amount of TBphase gradually decreases.In addition,the micro-hardness decreases first and then increases with the increase of the aging temperature.