Magnetic Field Influence on the Mechanical Properties of 3D-Printed Magnetorheological Composites

Magnetorheological materials, such as ferromagnetic particle-reinforced composites, can be fabricated through magnetic-field-assisted processing to control particle distribution and orientation. However, accurately modeling their behavior remains challenging due to the intricate interactions between the ferromagnetic particles and the matrix. This research investigates how applying a magnetic field during additive manufacturing, also known as 3D printing, affects the alignment and distribution of the ferromagnetic particles, thereby influencing the material's mechanical properties. This is accomplished by using an iron-reinforced polylactic acid filament exposed to an external magnetic field produced by samarium-cobalt and neodymium-iron-boron magnets. ASTM D638 Type IV specimens using 0° and 90° raster patterns are printed under three conditions: a control group (no field), a single-magnet setup, and a dual-magnet setup. To quantify the iron particle alignment, two approaches for circular statistics methods were used: 1) a pixel-based gradient analysis and 2) a region-based orientation analysis. The findings demonstrate how magnetic fields can alter mechanical properties, suggesting the potential for microstructural control during fabrication. By examining the effects of particle orientation through tensile testing and complementing with a scanning electron microscope analysis, this study establishes the critical relationship between magnetic field direction and material performance, which is validated using circular statistics methods.