Influence of alloying elements on process dynamics during laser deep penetration welding

材料中的合金化元素会显著影响母材的材料性能。在激光深熔焊接中，表面张力及其温度梯度、熔体的蒸汽压和粘度是影响熔池行为的主要因素，也直接影响小孔的形成。小孔动力学和缺陷的形成受材料性能的影响，因此也受合金元素的影响。目前对这些相关性的研究还很有限，这将有助于更好地了解复杂的焊接过程，并可能通过合金元素设计来影响工艺行为和焊接缺陷。因此，本课题的目的是了解合金元素对铝激光深熔焊接飞溅形成的影响。挑战在于根据起源点及其频率分布来确定飞溅的特征(大小、速度和方向)。深合金化工艺可用于在铝板中产生均匀的合金化元素预分布。这些深合金化区域可以作为后续的平板堆焊试验的基础材料。根据合金元素的不同，在焊接过程中观察到飞溅特征及其起源点。

Alloying elements in materials can significantly influence the material properties of the base material. In laser deep penetration welding the surface tension and its temperature dependent gradient as well as the vapor pressure and the viscosity of the melt mainly influence the melt pool behavior and also directly the keyhole. Keyhole dynamics and formation of defects are affected by material properties and therefore by alloying elements. Limited research has been done to find out about these correlations which would help getting a better knowledge about the complex process and could offer a possibility to influence the process behavior and welding defects by alloying element design.Therefore, the aim of the project is to understand the influence of material properties affected by alloying elements on the spatter formation during laser deep penetration welding of aluminum. The challenge is to determine spatter characteristics (size, speed and direction) depending on the point of origin and their frequency distribution. The deep alloying process can be used to produce a homogeneous pre distribution of the alloyed elements in the aluminum sheet. These deep alloyed areas can be used as the base material for subsequent bead on plate welding experiments. Spatter characteristics and their points of origin are observed during welding depending on the alloying elements.