Large gains in strength and ductility are of little significance if the material’s anisotropy is high. Therefore, improving the mechanical properties and reducing the anisotropy of Al alloys obtained by additive manufacturing is a topic of growing interest. This manuscript examines the effect of distinct heat treatments on the mechanical, anisotropic, and microstructural behavior of a hypoeutectic, almost eutectic, AlSi11Cu alloy obtained by laser powder bed fusion (L-PBF). The microstructural characterization revealed an Al matrix surrounded by a Si-rich network, forming a coral-like pattern with a heterogeneous combination of columnar and equiaxed grains. The texture indicated that the columnar grains were preferentially oriented towards the building direction with strong Cube and Goss components. Different strength-ductility ratios were obtained following the annealing and solution heat treatments at different temperatures (200 °C–550 °C) with a holding time of 1 h. In terms of grain size and dislocation density, no significant changes were found in the microstructure, suggesting that grain size and dislocation strengthening mechanisms are not highly affected by the heat treatments. In addition, the Si-enriched network remained interconnected until 300 °C. At higher temperatures, this interconnection was lost, giving rise to large Si particles depleting the Si content in solid solution in the Al matrix. Digital image correlation maps revealed that deformation fields were more homogeneous when the cellular structure disappeared. The visco-plastic self-consistent model showed that when applying the load at 30° in the building direction (BD), the largest tensile strength was generated, whereas the lowest strength was obtained when the load was parallel to the BD. Heat treatments for 1 h holding time were found to be efficient in reducing the Lankford coefficients dispersion, suggesting improvements in formability and reducing the alloy’s planar anisotropy. These results revealed that annealing up to 400 °C or higher temperatures followed by water quenching leads to good strength and ductility ratios while reducing anisotropy.

如果材料的各向异性很高，那么强度和延展性的大幅度提高就没有多大意义。因此，提高通过增材制造获得的铝合金的机械性能和降低各向异性是一个越来越受关注的话题。本手稿研究了不同热处理对通过激光粉末床融合 (L-PBF) 获得的亚共晶、几乎共晶的 AlSi11Cu 合金的机械、各向异性和微观结构行为的影响。微观结构表征揭示了一个被富硅网络包围的铝基体，形成了一种珊瑚状图案，具有柱状和等轴晶粒的异质组合。纹理表明，柱状晶粒优先朝向构建方向，具有强Cube和Goss分量。在不同温度（200°C-550°C）下退火和固溶热处理后获得不同的强度 - 延展比，保持时间为1小时。在晶粒尺寸和位错密度方面，显微组织没有发现显着变化，表明热处理对晶粒尺寸和位错强化机制的影响不大。此外，在 300 °C 之前，富含 Si 的网络仍保持互连。在更高的温度下，这种互连会消失，从而产生大的 Si 颗粒，从而耗尽 Al 基体中固溶体中的 Si 含量。数字图像相关图显示，当细胞结构消失时，变形场更加均匀。粘塑性自洽模型表明，当在建筑物方向（BD）上施加 30° 的载荷时，产生最大的抗拉强度，而当载荷平行于BD时获得最低的强度。热处理 1 小时的保温时间被发现在减少兰克福德系数分散方面是有效的，表明可成形性的改善和降低合金的平面各向异性。这些结果表明，退火至 400 °C 或更高温度，然后进行水淬，可在降低各向异性的同时获得良好的强度和延展性比。