Multi-component nitride thin films usually show high hardness and good wear resistance due to the nanoscale structure and solid-solution strengthening effect. However, the state of N atoms in the thin film and its effects on the compressive strength is still unclear. In this work, (AlTiVCr)N multi-component nitride thin films with a face-centered cubic (FCC) structure prepared by the direct current magnetron sputtering method exhibit a superior strength of ~4.5 GPa and final fracture at a strain of ~5.0%. The excellent mechanical properties are attributed to the synergistic effects of the nanocrystalline structure, covalent bonding between N and metal atoms, and interstitial strengthening. Our results could provide an intensive understanding of the relationship between microstructure and mechanical performances for multi-component nitride thin films, which may promote their applications in micro- and nano-devices.

Alloying non-metallic elements can not only change the structure of alloys, but also tailor the mechanical and physical properties. The microstructure, mechanical and magnetic properties of (CoCrFeNi) _100-x Ge _x (molar ratio, x = 0 ∼ 33) high-entropy alloys (HEAs) have been systematically studied in this paper. The experimental results show that the (CoCrFeNi) _100-x Ge _x HEAs transform from a face-centered cubic (FCC) to a body-centered cubic (BCC) solid solution when 10 ≤ x ≤ 25, and a hexagonal intermetallic compound (IM) formed at x = 33. Tensile measurement revealed that the strength and plasticity of the alloy were enhanced simultaneously with Ge addition in the single FCC region (x ≤ 10), a decrease in ductility but sharp increase of strength was found in the alloys when the BCC phase starts to appear. Theoretical calculations and magnetic hysteresis loop measurements show that the alloys transform gradually from a paramagnetic to a ferromagnetic state at room temperature.

Magnéli phases exhibit significant potential for applications in electronic materials in energy conversion due to their high electrical conductivity and excellent thermal stability. In this study, single-phase Ti_nO_2n−1 (n = 4, 5, 6) bulk materials were successfully prepared by a combination of the carbothermal reduction of nano-sized rutile TiO₂ and hot-press sintering methods. The relationships between the phase evolution, microstructural features, and thermoelectric performance were investigated systematically. Synchrotron X-ray diffraction (SXRD) and scanning electron microscopy (SEM) analyses revealed that the Ti₄O₇ and Ti₅O₉ materials had single-phase structures with high densities (relative density > 97%) and no obvious grain boundary holes or microcracks. We tested the thermoelectric properties of the Magnéli phases in the temperature range of 300–1100 K. The Magnéli phases exhibited a significant temperature dependence, with peak zT values of 0.17, 0.18, and 0.14 for Ti₄O₇, Ti₅O₉, and Ti₆O₁₁, respectively, at 1100 K. This variation in thermoelectric performance was mainly attributed to the synergistic effect of the oxygen vacancy concentration and the shear surface density on the carrier concentration and lattice thermal conductivity. Furthermore, the Fermi energy levels and electronic thermal conductivity of the Magnéli phases were calculated using the single parabolic band (SPB) model.

The epitaxial La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 (L5BO3) thin films with varying oxygen vacancies were prepared on (001) SrTiO3 substrates in this work. These thin films exhibit a high degree of crystallinity and prominent semiconductor characteristics. The valence state of the B-site elements is influenced by the introduction of oxygen vacancies, which in turn affects the spin state. Electrical properties were investigated across a broad temperature range (150–400 K), demonstrating significant resistivity variations of up to 3 orders of magnitude as a function of oxygen vacancies. The corresponding mechanisms of small polaron hopping and variable range hopping are discussed. This work explores the effect of oxygen vacancies on the structure and performance of L5BO3 high-entropy oxide films prepared under various oxygen pressures, offering foundational insights into the compositional manipulation of high-entropy oxides.