Marco Pierre White

Project U02: Deep laser alloying for adjustment of finely graded alloy compositions

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• published: 04 Oct 2016
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Project U02 synthesizes micro samples of different alloy compositions. Microstructures of samples will be developed by thermal, mechanical or thermo-mechanical treatments and finally descriptors will be measured. For this purpose, a laser-based method is developed, by which reproducible alloys are allowed to be produced in fine graduation of the composition. This fullfills the requirements of a highthroughput method. In a first step, element layers are deposited on substrates by selective laser melting or by electrolytic deposition. In a further process step, the alloy will be produced through laser-based remelting the alloy element layers and mixing the elements with the substrate material. The aim is to produce homogeneous alloys with a given composition of alloy components. This requires a complete control of the deep-laser-alloying process in terms of the weld penetration and the homogeneity of the remolten pool. A desired remelted volume shall be guaranteed by in-situ measurement based on short-coherent interferometry. The alloying homogeneity can be acquired by in-situ measurement of the emission spectrum of processinduced plasma. In the study the influence of different scanning strategies on the homogeneity of the remolten pool should be examined. Various deposition states of element layers need to be investigate in terms of the suitability for homogeneous intermixing of the remolten pool. Another challenge is to homogenize the microstructures of samples intentionally. This requires a subsequent heat treatment with controllable cooling. Beside the deep-laser-alloyed micro samples, spherical micro samples from Project U01 are going to be heat treated by laser, in order to discover the dependence between applied parameter sets and resulted microstructures. http://www.uni-bremen.de/sfb1232