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Abstract No.: |
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Scheduled at:
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Wednesday, June 22, 2022, Saal Brüssel 3:20 PM Joining of glass, ceramics and metals
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Title: |
Joining of ceramics: brazes, surface activation, stress reduction and achieved properties
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Authors: |
Clemens Steinborn / Fraunhofer IKTS, Germany Hans-Peter Martin* / Fraunhofer IKTS, Germany Ino Rass/ Euromat GmbH, Germany
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Abstract: |
Joints of ceramics and aluminum alloys are of interest for lightweight structures with increased stiffness. Furthermore, lightweight sections subjected to thermal or frictional load can be reinforced by ceramic inserts. The production of a low-fault and mechanically stable joint between light metal alloys and ceramics will be the way achieving those goals. Keys for a successful brazing are wetting of the metallic melt on ceramic surface and the reduction of stress, caused by different coefficients of thermal expansion. Al-Cu-Si brazes have been investigated for ceramic-aluminum joints. A melting temperature below 540 °C ensures less thermal degradation of the aluminum alloy. Additionally stresses between ceramic and metal alloys are reduced, because of the lower temperature level of joining. Due to the lower input of thermal energy, no reaction layer is detected on the ceramic surface which is formed at higher temperatures by active components like titanium. Ultrasonic waves have been applied to the joint to improve the wetting of the braze onto the ceramic surface, instead. The quality of the joints, especially homogeneity and size of defects, has been compared on cross sections. The shear tensile strength of those samples reaches 100 MPa. The helium leakage rate was in the range of ? 10 6 mbar/ls.
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