Li, Xiao (ORCID:000000032096298X)

DOE OSTI2026

Aluminum bonded SmCo5 magnets with enhanced mechanical strength

Despite their versatility and easy manufacturability, polymer-bonded magnets find limited application due to their limited mechanical properties and temperature resistance. In this study, we developed mechanically robust, aluminum-bonded SmCo5 magnets by utilizing a low-temperature, shear-assisted friction consolidation technique. Bonded magnets with varying magnetic phase content were fabricated at processing temperature of 500°C, and their microstructures, magnetic, mechanical, and electrical properties were systematically investigated. The resulting bonded-magnets showed effective consolidation with nanocrystalline microstructures. Magnetic properties were found to be tunable through variations in binder phase content, with coercivity reaching values up to 15.3 kOe (1217.5 kA/m) and maximum magnetic energy product up to 3.6 MGOe (28.7 kJ/m3), which are comparable to other bonded magnets. Electrical resistivities were lower than the polymer-bonded magnets, but comparable to the sintered ones. We observed an average flexural strength of 223 MPa for 60 vol.% SmCo5/Al sample, which is nearly two times higher than the reported values for sintered and bonded Sm-Co magnets. Our research demonstrated an effective approach to fabricate metal-bonded permanent magnets with superior magnetic and mechanical properties potentially applicable for high temperature applications.

Poudel Chhetri, Tej Bahadur↗

DOE OSTI2026

Structural uniformity and compositional homogeneity of solid-phase alloyed rod

Solid-phase processes have emerged as an alternative to fusion-based alloying to avoid coarse microstructures, undesirable phase formation, and high energy consumption. However, achieving uniform distribution of alloying elements during friction-based processing remains challenging due to highly heterogeneous thermomechanical conditions. This work evaluates the structural uniformity and compositional homogeneity of Al–Cu–Zn alloyed rods produced by friction extrusion (FE) and establishes the role of the rotational speed to feed rate ratio (N/V) on alloying effectiveness. A systematic matrix of FE experiments was conducted at constant extrusion ratio with N/V values ranging from 3.7 to 300. Compositional uniformity was assessed along the rod length (ICP-OES), in three dimensions (X-ray computed tomography), and at the microscale (SEM–EDS), supported by a gray-level co-occurrence matrix (GLCM)–based homogeneity metric. Smoothed particle hydrodynamics (SPH) simulations were used to reveal material flow and thermomechanical fields. Results show that N/V = 100 produces a high-shear mixing zone that eliminates the unmixed core and enables near-full dissolution and dispersion of Cu and Zn. At lower N/V, a laminar flow region persists at the rod center, causing segregation and large composition gradients. The combined experimental–computational analysis provides mechanistic insight into the transition from fragmented particle dispersion to thermomechanically assisted metallurgical mixing. This study establishes processing–structure relationships for solid-phase alloying and provides guidance for achieving homogenized compositions comparable to wrought alloys via rapid, scalable FE processing.

Aluminum↗