研究不同热处理工艺对砂型铸造Al?2Li?2Cu?0.5Mg?0.2Sc?0.2Zr合金显微组织和力学性能的影响.设计三级固溶处理方案((460℃,32 h)+(520℃,24 h)+(530/540/550℃,4/12/24/32 h))和不同温度(125,175,225℃)时效处理方案用于比较.采用光学显微镜(OM)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析显微组织演变过程.结果表明,最佳固溶处理((460℃,32 h)+(520℃,24 h)+(530℃,12 h))可溶解大部分晶界第二相.透射电镜结果表明,经175℃时效8 h后,δ\'(Al3Li)颗粒均匀分布于基体中,并伴有少量板条状S\'(Al2CuMg)和片状T1(Al2CuLi)相.采用最佳热处理方案((460℃,32 h)+(520℃,24 h)+(530℃,12 h)+(175℃,8 h))可获得屈服强度为376 MPa、极限抗拉强度为458 MPa和伸长率为4.1％的最佳综合性能.“,”This study focused on modifying heat treatment schemes to enhance the mechanical properties of sand cast Al?2Li?2Cu?0.5Mg?0.2Sc?0.2Zr alloy. Different three-stage solution treatment schemes ((460 ℃, 32 h) + (520 ℃, 24 h) + (530/540/550 ℃, 4/12/24/32 h)) and aging temperatures (125, 175, 225 ℃) were designed for comparison. The microstructure evolutions were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the three-stage solution treatment of (460 ℃, 32 h) + (520 ℃, 24 h) + (530 ℃, 12 h) could dissolve most of the secondary phases. The TEM results illustrated that fine δ\'(Al3Li) particles were homogeneously distributed in the matrix after aging at 175 ℃ for 8 h, accompanied by a small amount of lath-shaped S\'(Al2CuMg) and plate-like T1(Al2CuLi) phases. The best comprehensive properties of yield strength of 376 MPa, ultimate tensile strength of 458 MPa and elongation of 4.1％ were obtained by the optimal heat treatment scheme ((460 ℃, 32 h) + (520 ℃, 24 h) + (530 ℃, 12 h) + (175 ℃, 8 h)).