Additive Manufacturing of Bulk Nanocrystalline FeNdB Based Permanent Magnets

Lab scale additive manufacturing of Fe-Nd-B based powders was performed to realize bulk nanocrystalline Fe-Nd-B based permanent magnets. For fabrication a special inert gas process chamber for laser powder bed fusion was used. Inspired by the nanocrystalline ribbon structures, well-known from melt-spinning, the concept was successfully transferred to the additive manufactured parts. For example, for Nd16.5-Pr1.5-Zr2.6-Ti2.5-Co2.2-Fe65.9-B8.8 (excess rare earth (RE) = Nd, Pr; the amount of additives was chosen following Magnequench (MQ) powder composition) a maximum coercivity of µ0Hc = 1.16 T, remanence Jr = 0.58 T and maximum energy density of (BH)max = 62.3 kJ/m3 have been achieved. The most important prerequisite to develop nanocrystalline printed parts with good magnetic properties is to enable rapid solidification during selective laser melting. This is made possible by a shallow melt pool during laser melting. Melt pool depths as low as 20 to 40 µm have been achieved. The printed bulk nanocrystalline Fe-Nd-B based permanent magnets have the potential to realize magnets known so far as polymer bonded magnets without polymer.

Physical and Mechanical Properties of the Amorphous and Nanocrystalline Alloys

An amoprphous and nanocrystalline ribbon is produced applying the technology of rapid molten metal quenching. The chemical composition of the alloy is required to contain elements ensuring the amorphous structure formation in the course of quenching. A great number of various chemical elements in amorphous and nanocrystalline alloys contribute to the complex process of the structure formation in the course of heat treatment of the amorphous precursor. After heat treatment, the structure of the soft magnetic material can remain amorphous or partially crystallized or nanocrystalline. The results of an investigation into the melts’ property of iron-based amorphous and nanocrystalline alloys are presented in the paper. The structure has been shown to influence mechanical properties of the material in preparing the melt before casting.

Brazing of Metals, Alloys and Ceramics Using Rapidly Quenched Ribbon-Type Filler Metal STEMET

The work shows the main results on the development at NRNU MEPhI of rapidly quenched amorphous and nanocrystalline ribbon-type and powder brazing filler metals based on Al, Cu, Ni, Ti and Zr and their application for brazing of a wide range of materials in nuclear, thermonuclear, aerospace, automotive, aircraft and other industries: from steels, alloys and refractory metals to various ceramics without metallization of their surfaces.