Fabrication of high strength aluminum alloys using laser-based powder bed fusion (L-PBF) encounters challenges, including the occurrence of solidification cracks and the loss of volatile elements, such as Zn and Mg. The current work developed a Si-modified Al7075 alloy aiming at introducing eutectic phases to mitigate the solidification cracking during L-PBF. Based on Kou’s model, the addition of Zn and Mg decreased the crack susceptibility from 6504 °C to 5966 °C, and the addition of 3.74 wt pct of Si further decreased the crack susceptibility to 3960 °C. The Al7075 alloy fabricated by L-PBF exhibited a large amount of solidification cracks extending throughout the sample. Crack-free samples with a relative density of 99.94 pct, as inspected by X-ray microcomputed tomography, were achieved for the developed Si-modified Al7075 alloy. The microstructure showed a transition from a coarse columnar microstructure to a refined mixed columnar + equiaxed microstructure after alloy modification, with a concomitant grain size reduction from 59.0 ± 42.2 to 15.0 ± 9.4 µm. Moreover, Si, Mg₂Si, and Al₂Cu phases were detected in the Si-modified Al7075 alloy. After a direct ageing heat treatment, the Si-modified Al7075 alloy showed minimal age hardening effect with a peak hardness of (146 ± 3 Hv).

使用基于激光的粉末床熔合（L-PBF）制造高强度铝合金遇到了挑战，包括凝固裂纹的发生和诸如Zn和Mg等挥发性元素的损失。目前的工作是开发一种硅改性的Al7075合金，旨在引入共晶相以减轻L-PBF期间的凝固裂纹。基于Kou模型，Zn和Mg的添加将裂纹敏感性从6504℃降低至5966℃，并且3.74wt％的Si的添加进一步降低了裂纹敏感性至3960℃。由L-PBF制造的Al7075合金在整个样品中均显示出大量的凝固裂纹。通过开发的Si改性Al7075合金，通过X射线计算机断层扫描检查，获得了相对密度为99.94 pct的无裂纹样品。μ微米。此外，在Si改性的Al7075合金中检测到Si，Mg ₂ Si和Al ₂ Cu相。经过直接时效热处理后，Si改性Al7075合金显示出最小的时效硬化效果，峰值硬度为（146±3 Hv）。