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| Abstract No.: |
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Scheduled at:
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Wednesday, May 22, 2019, Saal Brüssel 12:00 PM
Properties of brazed joints 2
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| Title: |
In-situ observation of crack propagation in brazed joints
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| Authors: |
Thomas Uhlig* / Chemnitz University of Technology, Germany
Guntram Wagner / Chemnitz University of Technology, Germany
Sebastian Weis/ University of Applied Sciences Zwickau, Germany
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| Abstract: |
The knowledge of crack initiation and propagation in brazed joints provides new possibilities for the adaption of brazing processes or the development of new brazing fillers. Due to the high strength of the braze metal, which is almost the strength of the base material, rupture often occurs in the base material. Therefore, it is difficult to observe the crack propagation through the joint when tensile tests or tensile shear tests are conducted. This work deals with a test method, that allows an in-situ observation during the crack propagation by SEM. Two pieces of base material are brazed face to face in order to achieve a narrow long sample for the three-point bend test. The surfaces are ground and polished and the center of the sample including the joint is notched by a metallographic cutter. Consequently, the region of interest consists of the joint and some surrounding base material on both sides. The bend tests are carried out under path controlled conditions. The microstructure of the joint strongly affects the crack propagation. The crack runs through intermetallics, which mostly occur in the center of the braze metal, without plastic deformation. Eutectic and solid solution regions of the braze metal are deformed. The arising slip-lines can be seen distinctly.
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