Alloy design for additive manufacturing: Continuously reinforced Al-Ce nanocomposites
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36 MATERIALS SCIENCE↗
Engineering topics
Amon, Alfred
Publications and source records attributed to Amon, Alfred.
Aluminothermic reduction of CeO 2 : mechanism of an economical route to aluminum–cerium alloys
Time-resolved X-ray diffraction enabled mechanistic insight into the aluminothermic reduction of CeO 2 . The environmentally friendly process enables a direct route to Al–Ce alloy production and a high-value use for excess Ce from rare earth mining.
36 MATERIALS SCIENCE↗
Influence of atomic ordering and cerium doping on magnetostrictive Fe-Al alloys
Magnetostrictive iron-aluminum alloys can be a low-cost, mechanically stable alternative to iron-gallium and rare earth-iron alloys. The magnetostrictive performance of polycrystalline Fe-Al (alfenol) with 13–24 at. % Al was investigated, studying the role of compositional variation and thermal history. It was found that rapid cooling enhances the magnetostrictive response, and peak magnetostriction was found in Fe 78 Al 22 by high temperature annealing followed by quenching. Synchrotron diffraction enabled a direct correlation of magnetostrictive behavior and the transition from short-range order to long-range ordered cluster domains in the material which can be suppressed by rapid cooling. Following recent success of doping Fe-Ga with rare earth elements, we investigated the influence of Ce doping on improving magnetostriction and found that Fe-Al shows negligible solubility for cerium, inhibiting potential magnetostriction enhancement. In conclusion, our results illustrate the complex interplay between phase stability, ordering, and optimized magnetostrictive response.
36 MATERIALS SCIENCE↗
Local Order in Liquid Gallium–Indium Alloys
Liquid metals such as eutectic Ga–In alloys have low melting points and low toxicity and are used in catalysis and micro-robotics. This study investigates the local atomic structure of liquid gallium-indium alloys by a combination of density measurements, diffraction data, and Monte-Carlo simulation via the empirical potential structure refinement approach. A high-Q shoulder observed in liquid Ga is related to structural rearrangements in the second coordination shell. Structure analysis found coordination environments close to a random distribution for eutectic Ga–In alloy, while electronic effects appear to dominate the mixing enthalpy.
36 MATERIALS SCIENCE↗
Enhanced magnetostriction through dilute Ce doping of Fe-Ga
Doping of magnetostrictive galfenol (Fe 82 Ga 18 , in at.%) with rare-earth elements significantly enhances magnetostriction, with the largest gains achieved in textured melt-spun ribbons. Here, it is demonstrated that even extremely dilute Ce, as little as 65 ppm, can double the magnetostrictive response of galfenol when coupled with an appropriate heat treatment. This improvement is correlated with a compression of the host lattice, both of which reach their maximum extent at the calculated solubility limit of Ce in in body-centered cubic (bcc) galfenol, ~ 50 ppm. Beyond this point, excess Ce segregates into CeGa 2 , which forms an interdendritic network throughout the sample at high Ce levels and cannot be resolutionized through heat treatments. These findings point to the importance of solubility limits (i.e., equilibrium thermodynamics) in determining appropriate doping levels or heat treatment couples to optimize magnetostrictive performance, confirming that overdoping is actively detrimental to both material properties and cost.
36 MATERIALS SCIENCE↗