Design, fabrication and evaluation of metal-matrix lightweight magnetostrictive fiber composites

A class of lightweight FeCo/AlSi magnetostrictive composites was prepared in this study to explore the feasibility for 1-3 metal-matrix magnetostrictive materials for serving as sensors, actuators and energy harvesters. The FeCo fibers were inset into the AlSi metal liquid and then the composites were solidified at a protective atmosphere. The microstructural observations for these FeCo/AlSi composites illustrate the presence of the element diffusion and the disappearance of the cold-rolled preferred orientation. The refined microstructure was obtained during solidification and then further improved the magnetostrictive properties of the FeCo/AlSi composites. A zigzag interface with well transfer in stress and strain between the FeCo fiber and AlSi matrix existed through both physical and chemical bonding. There are two different experimental groups in this work. One group is aimed to evaluate the effect of the diameter of the FeCo/AlSi composite on the output voltage under compression. Another group with different numbers of the FeCo fibers is employed for analyzing the effect of the volume fraction of the FeCo fiber on the output performance. The results exhibit that a smaller diameter for the lightweight 1-3 FeCo/AlSi composite contributes to exciting a greater output voltage. Furthermore, the output voltage is proportional to the number of the FeCo fiber. An optimal resistive load of 500 Ω for this harvesting setup is obtained. Theoretical analysis through a magneto-mechanical coupling model for the FeCo/AlSi composites was conducted for accurately predicting the practical output performance.