%0 journal article
%@ 0043-2288
%A Chung, W.S.,Hummel, M.,Spurk, C.,Häusler, A.,Olowinsky, A.,Häfner, C.,Beckmann, F.,Moosmann, J.
%D 2024
%J Welding in the World
%N 
%P 43–50 
%R doi:10.1007/s40194-023-01616-1
%T In situ X-ray phase contrast imaging of the melt and vapor capillary behavior during the welding regime transition on aluminum with limited material thickness
%U https://doi.org/10.1007/s40194-023-01616-1
 
%X The X-ray phase contrast imaging is a powerful method to understand the fundamental behavior of the melt and keyhole during the laser beam welding process. In this paper, the keyhole-induced vapor capillary formation in the melt pool is investigated by using an adjustable laser beam source. For this purpose, the aluminum A1050 specimen with a thickness of 0.5 mm is molten only with the heat conduction welding regime by using the ring-mode laser beam. Once the specimen is molten through, the core multi-mode laser beam is then applied to vaporize the melt and a transition to keyhole welding regime occurs. Therefore, the core multi-mode laser beam with an intensity value of 33.3 MW/cm2 is investigated. The correlation between the keyhole-induced vapor capillary and the melt behavior is further investigated in this paper which was recorded with a high sampling rate of 19 kHz. In addition, a theoretical calculation about the keyhole depth is discussed in this paper.