Brazing allows joining different materials in order to combine their specific advantages and features for applications in several industry fields, such as automotive production, aeronautics and plastic processing. The design of brazed components must be flexible and related to a reasonable cost and effort. This analysis has to consider the application, since high temperatures and an aggressive environment can strongly influence the performance of a component. However, today a systematic approach to design brazed joints still does not exist. Furthermore reliable physical and mechanical data are not available. Such data are a valid benchmark to design a component.
This research work introduces a method to design brazed joints and predict their mechanical behaviour in service, in order to reduce developing times of reliable brazed joints. Eight well-known brazed joints were selected to verify this design approach. In a first step, the analysis of the physical and mechanical data of the considered filler metals and the base materials allowed to evaluate their compatibility with regard to the heat conduction, expansion and mechanical behaviour. Finally, the brazed joints were mechanically tested under different conditions and loads to estimate their behaviour in the application for which they are predestined. High temperatures and different corrosive environments were considered. Both quasistatic and dynamic mechanical loads were applied. Finally, not only pure normal or shear stresses were considered, but complex loads, too. The relationship between the microstructure and the mechanical performance was investigated to better understand the results achieved.
Even if the considered test conditions could not completely reproduce the real service conditions, the comparison with the behaviour of different brazed joints provided important information to support the designer in this sensitive development phase.