Casting process and comparison of the properties of adapted load-sensitive magnesium alloys

Abstract

Magnetic magnesium alloys can be utilized as a load sensitive material, in which the inverse magnetostrictive effect is used in order to measure the actual loads in structural components manufactured from such lightweight sensor alloys. To achieve a material which exhibits magnetic properties, Mg is alloyed with ferromagnetic materials like cobalt or samarium-cobalt. Alloying elements commonly used with Mg are utilized to improve the mechanical properties of these alloys, which however may have a slight negative impact on the magnetic sensitivity. In this work, two separate magnetic Mg alloys are compared, each with properties matched to the opposing requirements: (a) high load sensitivity and (b) satisfactory mechanical properties, respectively. The precipitation behavior of the ferromagnetic constituent Co in Mg together with other alloying elements is shown on the basis of SEM images. In addition, the dissolving behavior of the Co powder during the casting process of a binary Mg–Co alloy is investigated. Cyclic loading tests employing harmonic analyses of eddy current signals are utilized in order to verify the alloys’ sensory properties. The mechanical properties are investigated using tensile tests.