Material Technological Concepts for Diffusion Bonding of Titanium-Steel- and Magnesium-Steel-Joints

• Applicant: Professor Dr.-Ing. Wolfgang Tillmann
• Subject Area: Production Automation and Assembly Technology
• Term: from 2010 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 180583184

The metallurgical bonds between steel and light metals such as titanium or magnesium are among the most demanding bonding pairs. Due to oxide layers, intermetallic precipitates in the joint zone, and an unfavorable melting behavior, most conventional joining techniques fail when applied to light metals. During the applied processing period, a new bonding process, based on diffusion brazing has been developed for joining titanium-steel and magnesium-steel. Using PVD coatings, the selected additional materials were deposited on the joining partners. Then Ti-Ti- and Ti-St- as well as Mg-Mg- and Mg-St-brazements were carried out in a vacuum furnace. The metallurgical tests show that the well brazed joints were achieved without major brazing defects. Particular attention was paid to the precipitation of intermetallic phases, which were studied in detail by means EDX analyses. The mechanical properties of diffusion brazed joints correlated with the results of the metallurgical microstructure examinations.In the continuation phase, the presented work program will be carried out as planned. Based on the first working period, the obtained results will be transferred to brazements of the industrially highly relevant 1.4301 stainless steel and titanium alloy Ti6Al4V as well as the stainless steel and magnesium alloy AZ31. The purposes of this continuation application are to carry out extensive and fundamental investigation and clarification of the diffusion mechanism between the used PVD coatings and base materials. By eliminating the formation of intermetallic phases, high-strength Ti-St- and Mg-St-brazing joints can be achieved.

• DFG Programme: Research Grants