Plastic-deformation-assisted method has positive effect on regulating microstructure and mechanical properties of additive manufacturing (AM) metal samples. However, when fabricating weakly rigid metal samples by laser directed energy deposition (LDED), there are great limitations in the applicability and process flexibility of the commonly used rolling deformation auxiliary methods, which needs to be further improved. In this study, a synchronous-hammer-forging-assisted laser directed energy deposition (SHLDED) method is developed, and the effect of synchronous-hammer-forging on the microstructure and mechanical properties of LDED-processed 316L stainless steel samples is investigated. The results show that large plastic deformation up to 21 % of deposited materials can be achieved using a small hammering force of 55 N. Compared with LDED sample, the microstructure of SHLDED sample shows obvious equiaxed grains and refinement effect. The maximum intensity of the pole figure decreases by 50 % and the average grain size decreases by 69 %. Owing to the combined effect of grain refinement and work hardening, the yield strength (YS), ultimate tensile strength (UTS), and microhardness of SHLDED sample reach 494 ± 19 MPa, 677 ± 7 MPa, and 243 ± 11 HV_0.2, respectively, which are 41 %, 10 %, and 22 % higher than those of LDED sample. This study provides a new method for microstructure and mechanical properties regulation of LDED metal samples.

塑性变形辅助方法对调节增材制造 (AM) 金属样品的微观结构和力学性能具有积极作用。然而，在激光定向能量沉积（LDED）制备弱刚性金属样品时，常用的轧制变形辅助方法的适用性和工艺灵活性存在很大局限性，需要进一步提高。本研究开发了一种同步锤锻辅助激光定向能量沉积 (SHLDED) 方法，研究了同步锤锻对 LDED 处理的 316L 不锈钢样品的显微组织和力学性能的影响。结果表明，使用 55 N 的小锤击力可以实现高达 21% 的沉积材料的大塑性变形。与 LDED 样品相比，SHLDED样品的显微组织表现出明显的等轴晶粒和细化效果。极图的最大强度降低了 50%，平均晶粒尺寸降低了 69%。由于晶粒细化和加工硬化的综合作用，SHLDED 样品的屈服强度 (YS)、极限抗拉强度 (UTS) 和显微硬度分别达到 494 ± 19 MPa、677 ± 7 MPa 和 243 ± 11 HV_0.2分别比 LDED 样品高 41%、10% 和 22%。该研究为LDED金属样品的微观结构和力学性能调控提供了一种新方法。