Description:

Reducing the energy losses is a key requirement in the development of soft magnetic materials and their components. Among the bulk metallic glass (BMG) systems, Fe-based BMGs are most attractive for engineering applications due to their low raw material cost, excellent magnetic properties, ultra-high strength, and good corrosion resistance [1]. Fe-BMGs exhibit high saturation magnetization, low coercivity and low magnetostriction, and a relatively low conductivity [2]. In recent years, interest has focused on nano-crystalline soft magnetic alloys, whose magnetic properties benefit from their chemical and structural variations at the nanoscale. Nanocomposites can be engineered with distinct advantages over amorphous alloys in terms of high temperature stability and saturation magnetization, making them superior candidates for long-term operation [3]. Nanocrystalline commercial alloys are produced by annealing an amorphous alloy under optimal conditions in terms of annealing time, annealing temperature, and heating rate in order to precipitate α−Fe [4]. Unfortunately, the nano-crystalline Fe- BMG’s suffer from extreme embrittlement. Thus, they must be annealed in the final core geometry and handled very carefully. In recent years, the possibility of additive manufacturing of metallic glasses has drawn a lot of attention. In the Laser additive manufacturing (LAM) process, a thin layer of metallic powder is spread on a building plate. A laser beam selectively melts the powder, creating a dense layer. The building plate is lowered by one layer-height and gets recoated with powder. This process is repeated until the whole part is completed. This technique provides high heating and cooling rates, making it suitable for producing metallic glass parts with dimensions much bigger than their critical casting diameter. Besides the high heating and cooling rates, the layer-by layer construction of the part results in a complex heat treatment of the preceding layers. Understanding the behavior of metallic glasses under these high rates and complex treatment is the key to printing dense, crack-free parts with suitable magnetic properties.