Evaluation of Equiatomic CrMnFeCoNiCu System and Subsequent Derivation of a Non-Equiatomic MnFeCoNiCu Alloy.

Investigation into non-equiatomic high-entropy alloys has grown in recent years due to questions about the role of entropy stabilization in forming single-phase solid solutions. Non-equiatomic alloys have been shown to retain the outstanding mechanical properties exhibited by their equiatomic counterparts and even improve electrical, thermal, and magnetic properties, albeit with relaxed composition bounds. However, much remains to understand the processing-structure-property relationships in all classes of so-called high-entropy alloys (HEAs).

Nanoporous metal-polymer composite membranes for organics separations and catalysis.

Metallic thin-film composite membranes are produced by sputtering metal films onto commercial polymer membranes. The separations capability of the membrane substrate is enhanced with the addition of a 10 nm Ta film. The addition of a tantalum layer decreases the molecular weight cutoff of the membrane from 70 kDa dextran (19 nm) to below 5 kDa (6 nm).

Understanding the Time-Dependent Mechanical Behavior of Bimodal Nanoporous Si-Mg Films via Nanoindentation.

This study addresses the mechanical response of nanoporous Si-Mg films, which are fabricated using free-corrosion dealloying and which represent an intriguing form of silicon that may find use as an anode material in lithium-ion batteries. The porous thin-film samples, in both the as-dealloyed and annealed states, are designed to have a final thickness of ≈1 µm so that substrate effects can be avoided during mechanical characterization in both the time and frequency domains. The as-dealloyed and annealed samples are investigated using a modified continuous stiffness measurement (CSM) technique that optimizes the ability to achieve steady-state harmonic motion, such that accurate phase angle measurements can be obtained; the as-dealloyed and annealed samples exhibit distinct phase angles of 1.

Near-Surface Material Phases and Microstructure of Scandate Cathodes.

Scandate cathodes that were fabricated using the liquid-solid process and that exhibited excellent emission performance were characterized using complementary state-of-the-art electron microscopy techniques. Sub-micron BaAl₂O₄ particles were observed on the surfaces and edges of tungsten particles, as seen in cross-section samples extracted from the scandate cathode surface regions. Although several BaAl₂O₄ particles were observed to surround smaller Sc₂O₃ nanoparticles, no chemical mixing of the two oxides was detected, and in fact the distinct oxide phases were separately verified by chemical analysis and also by 3D elemental tomography.