Examinations for electron beam short cycle hard soldering

• Applicant: Professor Dr.-Ing. Horst Biermann, since 9/2022
• Subject Area: Coating and Surface Technology ; Metallurgical, Thermal and Thermomechanical Treatment of Materials ; Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 493122212

The project aims to deeply investigate the technological benefits andmaterial mechanisms of a short-time soldering process using anelectron beam (EB) in a soft vacuum (<10-3 mbar) for a targeted,local joining of Ni-based alloys as well as the effects on themechanical behaviour. The selection of the Ni-base alloy (INCONEL718) and the HTLx filler materials was made primarily witha view to the broad industrial application at high temperatures. The background is thedevelopment of an energy and material saving technology. Based onthis knowledge, a conclusion shall be drawn regarding the potentialsand limits of local electron beam brazing. This includes the holisticconsideration of the formation and joining of the brazed seam, theresulting stressability of the joint and corresponding knowledge-basedoptimisation measures for process stabilisation. The project will breaknew scientific ground regarding the local high-temperature brazing ofNi-based alloys using the EB, i.e. to the knowledge of the applicant,no results are available in the literature. On the one hand, theinvestigations are focused on the relationship between the processparameters (energy input/distribution) and the microstructure/propertychanges in order to generate stress-resistant solder joints. On theother hand, design specifications for the gap geometry are to bedeveloped on the basis of a simulation-assisted design of the thermaleffects on distortion and verified by experiments. The FEM-basednumerical calculations provide information on the local displacement and the sensitivity of the joint system for several process parameters,which is to be used for a more targeted heat input during short time soldering. Components forthe design of the joints are mainly defined temperatures ortemperature ranges at which phase transitions and/or structuralchanges occur. Based on this new, currentlyunavailable basic knowledge, the stress behaviour and the types ofdamage are to be investigated in detail by means of mechanical testssuch as shear- and hardness-tests. As a result, stress-related brazedjoints between Ni-based alloy and Ni-based solder should beavailable with a comprehensive understanding of their specificproduction and stressability.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Dr.-Ing. Lars Halbauer, until 8/2022