Laser powder bed fusion (L-PBF) offers significant potentialities for the design of complex part geometries. Due to the specific combination of properties, tungsten heavy alloys are used for special applications such as X-ray and γ-radiation shielding, balancing weights, collimators and molds. For optimum performance, complex geometries can be required in those applications. L-PBF of tungsten heavy alloys such as W-Ni-Fe is challenging due to the high thermal conductivity, high viscosity of the liquid phase, the high melting point and sensitivity to thermal cracking. The effect of L-PBF processing parameters on the material microstructure is therefore studied for different W-Ni-Fe powders, applying substrate preheating temperatures up to 800 °C. Furthermore, the impact of thermal post-treatment is investigated, leading to a microstructure close to conventionally sintered material. Crack-free samples can be generated from all powders, but residual and heterogeneously distributed pores are still detected. It is shown that evaporation of NiFe binder matrix during L-PBF is significantly lower for pre-alloyed powders than for mixed powders.

激光粉末床熔合 (L-PBF) 为复杂零件几何形状的设计提供了巨大的潜力。由于特性的特定组合，钨重合金用于特殊应用，例如 X 射线和 γ 辐射屏蔽、平衡重、准直器和模具。为了获得最佳性能，在这些应用中可能需要复杂的几何形状。由于高导热性、液相的高粘度、高熔点和对热裂的敏感性，钨重合金（如 W-Ni-Fe）的 L-PBF 具有挑战性。因此，针对不同的 W-Ni-Fe 粉末，研究了 L-PBF 加工参数对材料微观结构的影响，将衬底预热温度提高到 800 °C。此外，研究了热后处理的影响，导致接近传统烧结材料的微观结构。可以从所有粉末中生成无裂纹样品，但仍可检测到残留和不均匀分布的孔隙。表明 Ni 的蒸发L-PBF 过程中，预合金粉末的铁粘合剂基体明显低于混合粉末。