In the present study, multi-objective optimization is employed to develop the optimum heat treatments that can achieve both high-mechanical performance and non-distinctive crystallographic texture of 3D printed Inconel 718 (IN718) fabricated by laser powder bed fusion (LPBF). Heat treatments including homogenization at different soaking times (2, 2.5, 3, 3.5 and 4 h) at 1080 °C, followed by a 1 h solution treatment at 980 °C and the standard aging have been employed. 2.5 h is found to be the homogenization treatment threshold after which there is a depletion of hardening precipitate constituents (Nb and Ti) from the γ-matrix. However, a significant number of columnar grains with a high fraction (37.8%) of low-angle grain boundaries (LAGBs) have still been retained after the 2.5 h homogenization treatment. After a 4 h homogenization treatment, a fully recrystallized IN718 with a high fraction of annealing twins (87.1%) is obtained. 2.5 and 4 h homogenization treatments result in tensile properties exceeding those of the wrought IN718 at both RT and 650 °C. However, considering the texture requirements, it is found that the 4 h homogenization treatment offers the optimum treatment, which can be used to produce IN718 components offering a balanced combination of high mechanical properties and adequate microstructural isotropy.

中文翻译：

---

激光粉末床熔合工艺制备Inconel 718高温合金的后处理工艺优化

在本研究中，采用多目标优化来开发可以实现高机械性能和通过激光粉末床熔合（LPBF）制成的3D打印Inconel 718（IN718）的无区别晶体学织构的最佳热处理。已采用热处理，包括在1080°C的不同浸泡时间（2、2.5、3、3.5和4 h）下均质化，然后在980°C进行1 h固溶处理并进行标准时效处理。发现均化处理阈值为2.5 h，此后从γ矩阵中耗尽了硬化的沉淀成分（Nb和Ti）。但是，经过2.5小时的均质化处理后，仍然保留了大量具有高比例（37.8％）的低角度晶界（LAGB）的柱状晶粒。经过4小时均质处理后，得到了完全重结晶的IN718，其退火双晶的比例很高（87.1％）。在室温和650°C下，经过2.5和4 h的均质处理，其拉伸性能超过了锻造的IN718。但是，考虑到纹理要求，发现4 h均质化处理提供了最佳处理，可用于生产IN718组件，这些组件提供了高机械性能和足够的微观结构各向同性的平衡组合。