The processing of conventional alloys by laser-based additive manufacturing can be challenging, particularly for alloys prone to hot cracking. However, additive manufacturing offers the possibility to produce novel alloys with improved properties, which cannot be achieved by other processing methods.

Although several studies have demonstrated the positive influence of Zr addition on crack prevention of Al alloys tailored to additive manufacturing, its influence on the formation of strengthening precipitates in 2xxx alloys, remains largely unexplored. This work investigates the microstructure of a Zr-modified 2xxx AlCuMgZr alloy fabricated by laser powder bed fusion, with a particular emphasis on the precipitation of phases induced by the post-processing heat treatment, and their effects on mechanical properties.

The Zr addition successfully allows the consolidation of crack-free, dense material (>99.5%). The microstructure is characterized by fine, equiaxed grains (0.5–3 μm) which result from Al₃Zr-induced grain nucleation, with the grain boundary covered in eutectic S-Al₂CuMg. After optimized three-step heat treatment, nm-sized L1₂-Al₃Zr as well as S-Al₂CuMg rods strengthen the alloy, and lead to microhardness, young's modulus and yield strength of ∼1410 MPa, ∼82 GPa and ∼340 MPa, respectively. The results provide a basis for the understanding and further development of 2xxx alloys tailored to additive manufacturing.

通过基于激光的增材制造加工传统合金可能具有挑战性，特别是对于易于热裂的合金。然而，增材制造提供了生产具有改进性能的新型合金的可能性，这是其他加工方法无法实现的。

尽管一些研究已经证明添加 Zr 对专为增材制造定制的铝合金的裂纹预防有积极影响，但其对 2xxx 合金中强化析出物形成的影响仍未得到充分探索。这项工作研究了通过激光粉末床熔融制造的 Zr 改性 2xxx AlCuMgZr 合金的微观结构，特别强调了后处理热处理引起的相沉淀及其对机械性能的影响。

添加 Zr 成功地使无裂纹、致密的材料 (>99.5%) 固结。显微组织的特征是细小的等轴晶粒（0.5-3 μm），这是由 Al ₃ Zr 诱导的晶粒形核产生的，晶界被共晶 S-Al ₂ CuMg 覆盖。经过优化的三步热处理，纳米尺寸的 L1 ₂ -Al ₃ Zr 和 S-Al ₂ CuMg 棒材强化了合金，使合金显微硬度、杨氏模量和屈服强度达到~1410 MPa、~82 GPa 和~分别为 340 兆帕。结果为理解和进一步开发专为增材制造定制的 2xxx 合金提供了基础。