Fundamental research on a double beam laser process for metals

本项目提案旨在通过基础研究加强对一种特殊的双光束激光加工过程的理解。通过同时使用两个发射显著不同的激光辐射的激光源来定义该工艺，这两个激光辐射在工艺区域内启动不同的物理子工艺。该工艺本身可成功地应用于铝合金和铝钢副的激光钎焊。从这些前人的工作中可以推导出一个过程解释模型--这个模型包含几个开放的问题。因此，拟议工作的主要目标是弥合这些知识差距，以便提供一个全面的过程模型，特别是抑制物理子过程的相互作用。因此，将对每个子过程进行单独的工艺研究，这些子过程是：在激光照射区形成的温度场，在三相边界处诱导的热化学反应，以及熔融填充材料的润湿和扩散行为。作为主要成果，该技术可适用于各种材料和材料配对的钎焊。此外，该技术还可以应用于线基激光堆焊，克服了目前的工艺技术障碍。

The present project proposal aims on the enhancement of process understanding of a special double-beam laser process by means of fundamental investigations. The process is defined by simultaneous usage of two laser sources emitting significantly different laser radiation which initiate different physical sub-processes within the process zone. The process itself could be successfully applied on laser brazing of aluminum alloys as well as aluminum steel pairings. From these former works a process explaining model could be derived - this model however contains several open questions. Main objective of the proposed work thus is to close these gaps of knowledge in order to supply a comprehensive process model which inhibits particularly the mutual interactions of the physical sub-processes. Therefore separate process investigations will be conducted for each sub-process, which are: the temperature field, which forms in the laser irradiated zone, the induced thermos-chemical reactions at the 3-phase-border as well as the wetting and spreading behavior of the molten filler material. As main outcome the technique can thus be made applicable for brazing of various materials and material pairing. In addition the technique can be applied to wire based laser deposition welding, in terms that current process technological obstacle can be overcome.