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2122 |
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Tuesday, May 04, 2010, Sophia Room 2:10 PM Young Scientists |
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Coating of aluminum components with iron-based nanocrystalline solidifying materials to improve wear resistance
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Oliver Lehmann* / Technical University Berlin, Institute of technology, Berlin Johannes Wilden / Technical University Berlin, Berlin Victor E. Drescher/ Technical University Berlin, Berlin |
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The introduction of the controlled short arc technology within the last years offers the possibility to join heat sensitive materials like aluminium with minimized heat input. Aluminium alloys are used in a wide range of industrial applications and come more and more in use. However, the wear resistance of these alloys is insufficient in comparison to the steel ones. Therefore, the wear protection of aluminium surfaces is necessary. Cladding by overlay welding with iron-based materials represents an innovative approach for local protection of aluminium components, such as e.g. valve heads in combustion engines. The use of aluminium as parent material causes the formation of intermetallic phases. According to state of the art it is possible to join aluminium and iron-based materials by brazing but welding does not work. Because of the different melting temperatures, elasticity moduli and intermetallic phases, problems occur during the cooling-off time or during the operation. The recent progress in material science and welding technology reveals that the use of controlled short arc technology and new iron-based materials for cladding enable to fulfill the task; the heat input is lower and the alloys promote a nanocrystalline solidification. In the present work, the design of experiments and data evaluations were systematically applied to get the first results about the dependence between the controlled arc process parameters and the iron-based claddings of aluminium substrates. The influence of the automated cladding process on the heat input, the penetration, the microhardness, the dilution and the formation of brittle intermetallic phases at the interface was investigated. Quantitative effects were determined by the use of statistical methods. |