This work describes a systematic alloy design strategy resulting in the development of a high strength aluminum alloy adopted for L-PBF. First, based on the composition of a reference Al-Cu-Mg alloy, three Al-Cu-Mg-Mn-Zr-based alloys were investigated using computational thermodynamic tools. Subsequently, the L-PBF processing behavior, microstructure, and concomitant mechanical properties of the L-PBF-fabricated alloys were investigated. Alloys with different compositions showed substantial differences in microstructure: the alloy without Zr addition showed a coarse columnar microstructure and suffered from solidification cracking, alloys with low to mediate Zr additions (1–1.98 wt%) showed a mixed columnar and equiaxed microstructure, while alloys with high Zr addition (3.72 wt%) showed a fully equiaxed microstructure, accompanied by a grain size reduction down to 0.7 ± 0.3 µm. All alloys containing ≥ 1.98 wt% Zr were crack-free. The L-PBF-processed Al-4.40Cu-1.51Mg-1.15Mn-3.72Zr (wt%) alloy showed an extended Zr solid solubility in the Al matrix of ~ 1.3 ± 0.1 wt%. Coherent primary Al₃Zr particles with a cubic L1₂ structure were formed in all the Zr-containing alloys. The mechanical properties of as-built alloys increased consistently with increasing Zr contents from 0 to 3.72 wt%. The designed Al-4.40Cu-1.51Mg-1.15Mn-3.72Zr (wt%) alloy combined a yield strength of 561 ± 24 MPa, an ultimate tensile strength of 580 ± 16 MPa, and an elongation at break of 6.0 ± 1.3%. The exceptionally high strength of this alloy is attributed to a combination of grain refinement, Orowan, solid solution, and dislocation strengthening. The current work shows the intrinsic potential of rapid solidification occurring during L-PBF for the fabrication of geometrically-complex, high-strength lightweight parts made of ultra-fine-grained hyper-peritectic aluminum alloys containing transition element additions.

这项工作描述了一种系统的合金设计策略，从而开发了用于L- PBF的高强度铝合金。首先，基于参考 Al-Cu-Mg 合金的成分，使用计算热力学工具研究了三种 Al-Cu-Mg-Mn-Zr 基合金。随后，L- PBF 的加工行为、微观结构和伴随的L研究了-PBF 制造的合金。不同成分的合金在微观结构上表现出显着差异：未添加 Zr 的合金显示出粗大的柱状显微组织并出现凝固裂纹，添加低至中等 Zr 的合金（1-1.98 wt%）显示出混合的柱状和等轴显微组织，而合金添加高 Zr (3.72 wt%) 的合金显示出完全等轴的微观结构，同时晶粒尺寸减小至 0.7 ± 0.3 µm。所有含有≥ 1.98 wt% Zr 的合金均无裂纹。的大号-PBF处理的Al-4.40Cu-1.51Mg-1.15Mn-3.72Zr（wt％）的合金在〜1.3±0.1重量％的Al基体显示出扩展的Zr的固体溶解度。具有立方 L1 _{2 的}相干初级 Al ₃ Zr 颗粒在所有含 Zr 合金中都形成了结构。随着 Zr 含量从 0 增加到 3.72 wt%，竣工合金的机械性能持续增加。设计的 Al-4.40Cu-1.51Mg-1.15Mn-3.72Zr (wt%) 合金的屈服强度为 561 ± 24 MPa，极限抗拉强度为 580 ± 16 MPa，断裂伸长率为 6.0 ± 1.3% . 这种合金的异常高强度归因于晶粒细化、Orowan、固溶和位错强化的组合。目前的工作显示了在L- PBF过程中发生的快速凝固的内在潜力，用于制造由含有过渡元素的超细晶粒超包晶铝合金制成的几何复杂、高强度轻质部件。