3DXRD study of recrystallization process in multilayer aluminum alloys during brazing

Important results from the project

Aluminum alloys offer unique properties for brazed heat exchanger products in terms of strength, corrosion resistance, and thermal conductivity. The brazing process itself causes complex structural transformations that affects the final properties. Development of such materials require a deep understanding of these transformations. This experiment aimed to follow the recrystallization and texture evolution during the brazing process using synchrotron diffraction.

Expected long term effects

The results provided a detailed understanding of the texture evolution of grain growth during simulated brazing. In-depth information about the recrystallization process and the methods developed will help Gränges to further develop these materials. The data is also expected to aid the development of a simulation tool for recrystallization by providing time-resolved data for verification and calibration.

Approach and implementation

The In-situ 3D X-ray diffraction method of beamline ID11 at the ESRF facility (Grenoble, France) was used to study texture evolution and grain growth while heating the sample to the brazing temperature. At each temperature, a full rotation of the sample at different heights was measured to access all texture components in different layers of the material. The diffraction contrast tomography method was used on the recrystallized sample at the end of the in-situ test to provide images of the shape of grains and also the absolute values of the grain sizes.