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Electric mobility is undergoing a very rapid maturation process [A. Kampker, K. Kreisköther, P. Treichel, T. Möller, Y. Boelsen, and D. Neb, “Electromobility trends and challenges of future mass production,” in Handbook Industry 4.0, edited by W. Frenz (Springer, Berlin, 2022), D. Ziegler and N. Abdelkafi, “Business models for electric vehicles: Literature review and key insights,” J. Cleaner Prod. 330, 129803 (2022)]. While conventional vehicle design disciplines such as car body design are established, electromobility-specific disciplines are in the technological orientation and ramp-up phase. In particular, the demand for components like batteries, e-motors, and power electronics is growing continuously [A. Kampker, K. Kreisköther, P. Treichel, T. Möller, Y. Boelsen, and D. Neb, “Electromobility trends and challenges of future mass production,” in Handbook Industry 4.0, edited by W. Frenz (Springer, Berlin, 2022), D. Ziegler and N. Abdelkafi, “Business models for electric vehicles: Literature review and key insights,” J. Cleaner Prod. 330, 129803 (2022)]. One of the major materials chosen for these parts is aluminum alloys [C. Prieto, E. Vaamonde, D. Diego-Vallejo, J. Jimenez, B. Urbach, Y. Vidne, and E. Shekel, “Dynamic laser beam shaping for laser aluminium welding in e-mobility applications,” Procedia CIRP. 94, 596–600 (2020)]. Next to the material-specific challenges and mentioned requirements, the focus is on the gas-tight welding of aluminum alloys for parts like casted power electronics housings and heat exchangers made of sheet metal or extrusion profiles. Gas-tightness is a requirement, on the one hand, to shield electronic components from the influence of the surrounding environment and, on the other hand, to prevent leakage of the water-cooling circuit [C. Prieto, E. Vaamonde, D. Diego-Vallejo, J. Jimenez, B. Urbach, Y. Vidne, and E. Shekel, “Dynamic laser beam shaping for laser aluminium welding in e-mobility applications,” Procedia CIRP. 94, 596–600 (2020), A. Artinov, M. Bachmann, X. Meng, V. Karkhin, and M. Rethmeier, “On the relationship between the bulge effect and the hot cracking formation during deep penetration laser beam welding,” Procedia CIRP 94, 5–10 (2020)]. This paper offers insight into the requirements of these parts and an innovative optics approach with a novel MultiFocus solution. Material-specific challenges (e. g. porosity), especially, for helium-tight welding of aluminum casted housings with forging alloys are characterized. This analysis is conducted using gas-tightness measurements, CT-scans, micrographs, and high-speed recordings in order to elaborate on the fundamental laser-material-process interdependencies and the correlation between the process and resulting quality, in terms of tightness. Furthermore, high-speed synchrotron recordings are conducted at the DESY and based on that, a detailed evaluation of laser and material interaction is conducted. This allows an explanation of the interactions for the prevention of pore formation in aluminum alloys and, thus, the characterization of the boundary conditions for a reliable process of gas-tight welding on aluminum alloys [C. Prieto, E. Vaamonde, D. Diego-Vallejo, J. Jimenez, B. Urbach, Y. Vidne, and E. Shekel, “Dynamic laser beam shaping for laser aluminium welding in e-mobility applications,” Procedia CIRP. 94, 596–600 (2020)].

No abstract

According to the state of the art most current forging parts and technical components are made of mono-materials. Nevertheless, parts consisting of only one material increasingly reach their specific material and constructive limits in the established production processes. Through use of previously joined raw parts consisting of different materials, it is possible to produce application-optimized hybrid parts. This paper describes the production chain of hybrid parts produced by combining two different joining processes with subsequent hot compression tests. The joining of various materials is realized by a deposition welding with a laser-stabilized gas-metalarc deposition welding (LGD) process and a conventional friction welding process. Subsequently, the hybrid samples are compressed under varying forming parameters such as temperature and deformation degrees. In order to characterize the joining zone, metallurgical investigations are carried out.

Compound forging is a technology to successfully manufacture hybrid parts by applying resource-saving process steps. During compound forging of steel-aluminum parts the formation of intermetallic phases is benefited. The thickness of these intermetallic phases influences the bonding and thus the global part quality. According to literature, specific coating elements reduce the phase seam thickness. In powder-metallurgically manufactured parts it is possible to selectively insert specific elements in the surface area. Therefore, a time intensive coating process can be avoided. The applicability of combining the technologies of powder-metallurgy and compound forging is discussed in this paper. Powder-metallurgically manufactured and solid parts made of steel and aluminum are compound forged and the influences on deformation behavior and the joining zone are investigated.