Laser powder bed fusion (LPBF) is an attractive technology of manufacturing high-strength aluminium alloy parts for the aircraft and automobile industries, limited by poor processability of these alloys. This work was aimed at finding the process window for the LPBF manufacturing of defect-free components of AA7075 alloy. Optimization of the parameters was performed at each stage of the multi-stage research, i.e. for single tracks, thin walls and volumetric specimens. At each stage, the relation between LPBF parameters and defect formation with a focus on hot cracking was investigated and discussed. Due to the optimization of process parameters, the density of volumetric specimens above 99 % was reached and vaporization losses of the alloying elements were significantly reduced, but solidification cracks could not be eliminated. It was found that solidification cracks were formed by the liquid film rupture mode, mainly along columnar grain boundaries. The EDS microanalysis showed intergranular microsegregation, not only of the main alloying elements (Zn, Mg, Cu) but also of minor elements such as Si. Silicon may play a significant role in increasing susceptibility to cracking by increasing the stability of the liquid film. Reduction in the silicon impurity content in the AA7075 powder gives a chance to reduce susceptibility to cracking with no change of the alloy specification.

激光粉末床熔合（LPBF）是制造用于飞机和汽车行业的高强度铝合金零件的一项有吸引力的技术，但这些合金的可加工性差。这项工作旨在寻找用于制造AA7075合金无缺陷部件的LPBF的工艺窗口。参数的优化是在多阶段研究的每个阶段进行的，即对于单轨道，薄壁和体积样本。在每个阶段，以热裂纹为重点，研究并讨论了LPBF参数与缺陷形成之间的关系。由于工艺参数的优化，达到了99％以上的体积试样密度，合金元素的汽化损失显着降低，但无法消除凝固裂纹。发现通过液膜破裂模式形成凝固裂纹，主要沿着柱状晶界形成。EDS显微分析表明，不仅主要合金元素（Zn，Mg，Cu）而且还存在次要元素（如Si）的晶粒间微偏析。硅可通过增加液膜的稳定性在增加裂纹敏感性中起重要作用。在不改变合金规格的情况下，降低AA7075粉末中的硅杂质含量可以降低开裂的可能性。硅可通过增加液膜的稳定性在增加裂纹敏感性中起重要作用。在不改变合金规格的情况下，降低AA7075粉末中的硅杂质含量可以降低开裂的可能性。硅可通过增加液膜的稳定性在增加裂纹敏感性中起重要作用。在不改变合金规格的情况下，降低AA7075粉末中的硅杂质含量可以降低开裂的可能性。