Electron beam multi step and multi process technologies for local materials engineering of magnesium alloys for a load related modification of surface properties (EB-MeMaRa)

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The custom-designed protection of Mg alloys against wear and corrosion is an urgent demand to extend the application fields of these advantageous light weight construction materials. Electron beam (EB) multi-step and multi-process technologies are excellently suitable for a local materials engineering regarding the load specific modification and optimization of surface properties. These effects in their entirety are realizable only by means of EB surface technologies using flexible process steps in connection with suitable thermal cycles and conditions of vacuum.The aim of the requested research project EB-MeMaRa is the establishment of scientific fundamentals for the generation of graded surface layers on Mg materials exhibiting increased stability against corrosion and wear. Basing on the positive results of the first project period within the scope of the follow-up application the interactions between EB and material will be extensively investigated using selected combinations of substrate and additional. The effects of process parameters on structure and properties will be researched to provide fundamental contributions for the process background.The reference material is the basic alloy AZ91 and as additive materials the alloys AlSi12 and AlSi30 are used for EB alloying (EBA), the combination of AlSi30+TiC is used for EB dispersion alloying (EBDA). For both technologies the additive materials are applied as wires and/or powders being deposited by means of arc plasma spraying (APS).The main point of interest are investigations into the wear and corrosion behavior of selected defect-free alloyed layers and dispersion alloyed layers showing novel structural features (e.g. supersaturated phases, intermetallic compounds, grain size and distribution of hard particles).Compared with the previous project the extended and new available measurement methods like a self-made hydrogen measuring probe as well as a new pin-on-disc tribometer contribute to an extended investigation of the acting wear and corrosion mechanism to define and generate optimal layer configurations.A successful realization of the requested project provides a contribution for the generation of significant requirements for a comprehensive industrial application of Mg light weight construction materials.