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In this study, magnesium is alloyed with varying amounts of the ferromagnetic alloying element cobalt in order to obtain lightweight load-sensitive materials with sensory properties which allow an online-monitoring of mechanical forces applied to components made from Mg-Co alloys. An optimized casting process with the use of extruded Mg-Co powder rods is utilized which enables the production of magnetic magnesium alloys with a reproducible Co concentration. The efficiency of the casting process is confirmed by SEM analyses. Microstructures and Co-rich precipitations of various Mg-Co alloys are investigated by means of EDS and XRD analyses. The Mg-Co alloys' mechanical strengths are determined by tensile tests. Magnetic properties of the Mg-Co sensor alloys depending on the cobalt content and the acting mechanical load are measured utilizing the harmonic analysis of eddy-current signals. Within the scope of this work, the influence of the element cobalt on magnesium is investigated in detail and an optimal cobalt concentration is defined based on the performed examinations.

Reducing inertial masses of engineering equipment or vehicles to lower their energy requirements necessitates the use of lightweight materials possessing high static and cyclic strengths for lower densities. If, in doing this, over dimensioning of mechanical components is to be avoided then a design which is precisely matched to the loading leads to high elastic stresses and strains in the material employed. In order to avoid over loading and plastic deformation, the service loads applied to the component must be monitored. With the aid of such measured loading history data, the resulting fatigue life can be derived so that the maintenance intervals can be planned and subsequent generations of components can be optimized. If the component possesses magnetic properties, it can serve as a self-sensoring device since relevant information about the operating conditions can be collected using the magnetic material. This information can be read out and processed during the component's service by utilizing modern methods of non-destructive component testing and material characterization such as high resolution eddy current technology using harmonic analysis.According to Bozorth, the magnetic domains' length in a ferromagnetic material changes as soon as the domains' direction of magnetization is modified (magnetostriction). [1] If this is related to entire component parts made of ferromagnetic materials then the change in the entire length is the sum of all the individual domain length changes. Inverse magnetostriction (also: Villari-Effect, named after Emilio Villari, Italian physicist 1836-1904) describes the change in magnetic susceptibility, the measure of a material's magnetizability, [2] during elastic deformation. Here, the material's magnetic properties change as a function of the operating mechanical stresses because the individual domains are aligned parallel to the direction of strain. The utility of the inverse magnetostriction effect to determine the applied mechanical forces has already been demonstrated in nickel by Kaleta and Ż ebracki. [3] According to this, the voltage measured by means of a coil increases proportionally to the operating mechanical stresses within the elastic range up to the yield point. Thus, on monitoring the component using measuring technology, the quantitative data can be collected for the instantaneously operating load condition. Klever et al. [**] This research is sponsored by the German Research Foundation (DFG) within the subproject E2 ''Magnetic Magnesium Alloys'' of the Collaborative Research Center 653 ''Gentelligent Components in their Lifecycle.'' Gentelligent (genetically intelligent) components describe a new kind of machine parts which are capable of collecting, pre-processing, and storing information (e.g., temperature and forces during use of the component).In this article, manufacture of a magnetic magnesium alloy based on the known magnesium alloys AZ91 or ZEK200 together with samarium-cobalt is investigated. The objective of the investigations is to produce an Mg ...

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