Evaporation pheanomena during selective electron beam melting and theri influence on material properties

组件的增材制造是未来的关键技术。基于粉末床的选择性电子束熔化工艺允许从高性能合金生产复杂部件。然而，高度动态的熔化过程并没有被完全理解，并且受到结合缺陷、合金成分变化和过程不稳定性的影响。该项目的目的是了解选择性电子束熔化过程中的基本机制，并利用这些知识来预测和影响所得材料的质量。为了达到这一目的，本文采用格子Boltzmann模型，对考虑选择性蒸发现象的电子束选择性熔化过程进行了数值模拟。蒸发导致材料损失，影响熔池动力学，改变合金成分。对粉末颗粒尺度的模拟揭示了束流、粉末和熔池之间复杂相互作用的结果。数值计算结果通过一个典型合金的实验进行了验证。

Additive manufacturing of components is a key technology of the future. The powder bed based selective electron beam melting process allows to produce complex components from high performance alloys. Nevertheless, the highly dynamic melting process is not fully understood and suffers from binding faults, changes of the alloy composition and process instabilities. Aim of the project is to understand the basic mechanisms during selective electron beam melting and to use this knowledge to predict and to influence the resulting materials quality. In order to reach this aim, the selevtive electron beam melting process takting selective vaporation phenomena into account is simulated based on a Lattice Boltzmann Model. Evaporation leads to material loss, has influence on the melt pool dynamics and changes the alloy composition. Simulation on the scale of the powder particles reveals phenomena which result from the complex interplay between beam, powder and melt pool. The numerical results are varified by experiments by an exemplary alloy.