It is common to use heat treatment process to control the microstructure of additive manufacturing parts and improve the mechanical properties. However, there are few reports about the control of microstructure properties of WAAM hybrid inter-layer hammering fabricated parts by heat treatment. In this study, the effect of annealing on microstructure and mechanical properties of inter-layer hammering hybrid wire arc additively manufactured aluminum alloy was studied. The ratio variation of fine grain (FG) and coarse grain (CG) regions, grain size and dislocations were analyzed, and the strength-plasticity mechanism was revealed. The results shown that with the increase of annealing temperature, the ratio of FG and CG region changed from 4:1–1:5, grain growth and recrystallization happened in FG and CG regions, respectively, dislocations mostly retained in FG region and released in CG region. With the introduction of annealing and the increase of annealing temperature, the strength of hybrid manufactured samples gradually weakened while the plasticity first improved and then reduced. The best tensile properties of ultimate tensile stress 366 MPa and elongation 29.2% were achieved at 180 °C annealing. Compared with as-deposited sample, the synergistic enhancement of strength and plasticity in annealed samples is owing to dislocation strengthening, grain refinement, and heterogeneous structural strengthening. Compared with hammered sample, the strength retained and significant improved in plasticity of annealed sample, owing to dislocation released, grain refinement and heterogeneous structural.

通常采用热处理工艺来控制增材制造零件的微观结构并提高机械性能。然而，关于通过热处理控制WAAM混合层间锤击加工件微观组织性能的报道还很少。本研究研究了退火对层间锤击混合丝电弧增材制造铝合金显微组织和力学性能的影响。分析了细晶粒（FG）和粗晶粒（CG）区域的比例变化、晶粒尺寸和位错，揭示了强度-塑性机制。结果表明,随着退火温度的升高,FG区和CG区的比例从4:1~1:5变化,晶粒长大和再结晶分别发生在FG区和CG区,位错主要保留在FG区,位错释放在FG区。 CG区域。随着退火的引入和退火温度的升高，混合制造样品的强度逐渐减弱，而塑性先提高后降低。在180℃退火时获得了最佳的拉伸性能，极限拉伸应力为366 MPa，伸长率为29.2%。与沉积态样品相比，退火样品的强度和塑性协同增强是由于位错强化、晶粒细化和异质结构强化。与锤击样品相比，由于位错释放、晶粒细化和异质结构，退火样品的强度得以保留，塑性显着提高。