Investigation of the influence of powder blends on production and materials technology aspects in Laser Powder Bed Fusion

增材制造（AM）是个性化和资源高效生产功能组件的关键技术。最重要的增材制造工艺之一是激光粉末床融合（LPBF），它允许在粉末床中逐层生产金属部件。然而，目前，由于缺乏适合LPBF的材料，LPBF技术的潜力无法充分发挥。目前，主要使用为常规铸造或锻造工艺开发的材料，例如1.4404、AlSi 10 Mg、Ti6 Al 4V或Inconel 718。工艺固有的条件，例如LPBF中极高的加热和冷却速率（约100%）。10^6 K/s），尚未专门开发和用于新材料的开发。因此，必须设计新的方法来实现新的LPBF材料的敏捷和有效的开发。通过混合不同的预合金粉末和/或元素粉末的合金生产和合金定制代表了一种新的方法。粉末的混合允许快速和灵活地调整合金成分，而不需要单独的粉末雾化。在初步工作中，已经证明了粉末混合物在LPBF工艺中通过工件的化学组成来调节机械性能的适用性。然而，有必要对粉末混合物在LPBF工艺链（粉末混合-涂覆-熔化-固化）中的行为进行沿着的基础研究，并对化学等效的预合金粉末进行比较。然而，当使用粉末共混物时会出现挑战（例如，某些类型的颗粒的不完全熔化），特别是由于各个粉末类型的物理性质（例如，密度、吸收系数）以及粉末颗粒的尺寸和形态的差异。为了验证粉末混合物在合金开发中的适用性，仍需要系统地研究和了解这些差异以及可能在LPBF工艺链沿着的各个工艺步骤中发生的任何粉末偏析对材料的微观结构、化学均匀性和机械性能的影响。目前，在粉末共混物中，粉末性质对工艺和所得工件性质的影响尚未探索。这一知识差距将通过这里申请的项目来弥补，并将与最先进的技术（使用预合金粉末）进行比较。

Additive manufacturing (AM) represents a key technology for the individualized and resource-efficient production of functional components. One of the most important AM processes is Laser Powder Bed Fusion (LPBF), which allows the layer-by-layer production of metallic components in a powder bed. At present, however, the potential of LPBF technology cannot be fully exploited due to the lack of materials suitable for LPBF. Currently, materials developed for conventional casting or forging processes, such as 1.4404, AlSi10Mg, Ti6Al4V or Inconel 718, are mostly used. Process-inherent conditions, such as extremely high heating and cooling rates in LPBF (approx. 10^6 K/s), are not yet specifically exploited and used in the development of new materials. Consequently, new approaches must be devised to enable agile and efficient development of new LPBF materials. Alloy production and alloy customization by mixing different pre-alloyed and/or elemental powders represents a new approach. Mixing of powders allows fast and flexible adaptation of the alloy composition without the need for separate powder atomizations. In preliminary works, the applicability of powder blends in the LPBF process for adjusting the mechanical properties via the chemical composition of workpieces has been demonstrated. however, fundamental investigations of the behavior of powder blends along the LPBF process chain (powder blending - coating - melting - solidification) and the comparison of chemically equivalent pre-alloyed powders are necessary. However, challenges (e.g. incomplete melting of certain types of particles) arise when using powder blends, due in particular to differences in the physical properties of the individual powder types (e.g. density, absorption coefficient) and the size and morphology of the powder particles. To validate the applicability of powder blends for alloy development, the effects of these differences and any segregation of powders that may occur in individual process steps along the LPBF process chain on microstructure, chemical homogeneity and mechanical properties of the material still need to be systematically investigated and understood. At present, the influence of powder properties on process and resulting workpiece properties in powder blends is unexplored. This knowledge gap is to be closed by the project applied for here, and a comparison is to be made with the state of the art (use of pre-alloyed powders).