Thermal protection systems of hypersonic vehicles typically require advanced high-temperature materials capable of withstanding long-term exposure to oxidizing environments at 1800–2500 ℃. However, related studies are scarce. Here, by employing a laser-assisted compositional engineering strategy, we successfully explore innovative high-entropy alumino-silicides (HEASs) that show superior long-term oxidation resistance across 1700–2100 ℃ for 80 min in air, surpassing the performance of previously reported ultrahigh-temperature materials. The oxidation resistance of HEASs is further validated by plasma ablation testing in air, exhibiting a linear ablation rate of as low as 0.035 μm·s⁻¹ at 2100 ℃. Such remarkable oxidation resistance is attributed to the formation of a unique alumino-silicate glassy phase. Further first-principles calculations coupled with experimental observations indicate an ultralow oxygen diffusion rate (4.26 × 10⁻⁵ cm²·s⁻¹) and exceptional thermal stability (binding energy of −0.004 eV·Å⁻²) in the alumino-silicate glassy phase due to multi-component synergistic effects. This work highlights the potential of HEASs for long-term ultrahigh-temperature applications.

Understanding the fundamental mechanisms of thermal expansion in high-entropy ceramics is crucial for their structural applications under extreme conditions. Here, we propose a machine learning (ML)-driven approach to reveal the different underlying mechanisms that govern the thermal expansion in high-entropy carbides (HECs) and high-entropy diborides (HEBs). Molecular dynamics simulations based on the well-fitted neuroevolution potentials are used to effectively collect the coefficient of thermal expansion (CTE) data of HECs and HEBs, and features with three levels, including the atomic level, the monolithic level, and the high-entropy level, are simultaneously considered to achieve reliable ML training. Five descriptors within a Linear Regression model are derived as the optimal combination for the accurate CTE prediction in HECs, where lattice distortion and its variation under temperature are revealed to have the dominant influence on suppressing the thermal expansion of HECs by strengthening ionic bonding and alleviating anharmonic effects. Conversely, the optimal combination of descriptors for the precise CTE prediction in HEBs is exclusively linked to fundamental parameters at both atomic and monolithic levels, highlighting the cocktail effects in impacting CTEs of HEBs. This work proposes an efficient framework for mechanism revelation by ML to facilitate the rational design of high-entropy ceramics with desired properties.

The exploitation of high-entropy rare-earth monosilicates (HEREMSs) with enhanced calcium-magnesium-aluminum-silicate (CMAS) corrosion resistance is vital for their potential applications as environmental barrier coatings (EBCs). Here, we present an inverse design strategy to explore HEREMSs with superior CMAS corrosion resistance. By high-throughput synthesis and dissolution experiments of equimolar 1–12-cation apatite powders at 1400 ℃, four optimized rare-earth elements, Lu, Yb, Er, and Nd, are determined to compositionally screen preferable high-entropy apatite with the lowest dissolution rate in CMAS melt, ultimately facilitating the inversely design of novel (Nd_2/15Er_3/5Yb_2/15Lu_2/15)₂SiO₅ (HEREMS-1). Further CMAS corrosion experiments have verified its superior CMAS corrosion resistance at temperatures up to 1500 ℃, exceeding the performance of previously reported EBC materials. Our work paves an alternative way for developing HEREMSs with exceptional CMAS corrosion resistance, making them highly suitable for future EBC applications.

Exploring superior calcium-magnesium-aluminosilicate (CMAS) corrosion resistance is crucial for high-entropy rare-earth monosilicates (HEREMs) as the next-generation environmental barrier coating (EBC) materials. However, related studies are rarely reported. This work presents the exploration of HEREMs with remarkable CMAS corrosion resistance by engineering their compositions. The equimolar 3-to-9 cation high-entropy rare-earth monosilicate (3-9HEREM) specimens were initially prepared using a pressure-less sintering technique; subsequently, their resistance to CMAS corrosion was evaluated at temperatures up to 1600 ℃. The results demonstrate that the 5HEREM specimens possess the best CMAS corrosion resistance among all the as-fabricated specimens, surpassing other reported EBC materials. Such remarkable CMAS corrosion resistance results from the generation of a dense apatite protective layer originating from its low dissolution rate at elevated temperatures.

Herein we establish formation ability descriptors of high-entropy rare-earth monosilicates (HEREMs) via the data-driven discovery based on the high-throughput solid-state reaction and machine learning (ML) methods. Specifically, adequate high-quality data are generated with 132 samples synthesized by the self-developed high-throughput solid-state reaction apparatuses, and 30 potential descriptors are considered in ML simultaneously. Two classifications are proposed to study the phase formation of HEREMs via the ML approach combined with the genetic algorithm: (Ⅰ) to distinguish pure HEREMs (X) from other phases and (Ⅱ) to categorize the detail phases of HEREMs (X2, X1, or X2+X1). Four formation ability descriptors ( $\overline{r_{\mathrm{M}\mathrm{e}}}$, $\overline{E_{\mathrm{F}}}$, ${\delta }_{E_{\mathrm{g}}}$, and ${\delta }_{Z^{\ast }}$) with a high validation accuracy (96.2%) are proposed as the optimal combination for Classification Ⅰ, where a smaller $\overline{r_{\mathrm{M}\mathrm{e}}}$ is determined to have the most significant influence on the formation of HEREMs. For Classification Ⅱ, a 100% validation accuracy is achieved by using only two formation ability descriptors ( $\overline{r_{\text{ion }}}$ and ${\delta }_{Z^{\ast }}$), where the $\overline{r_{\text{ion }}}$ is analyzed to be the dominant feature and a lower $\overline{r_{\text{ion }}}$ is beneficial to the formation of X2-HEREMs. Based on our established formation ability descriptors, 6,045 unreported multicomponent silicates are explored, and 3,478 new HEREMs with 2,700 X2-and 423 X1-HEREMs are predicted.

Understanding the initial oxidation mechanism is critical for studying the oxidation resistance of high-entropy diborides. However, related studies are scarce. Herein, the initial oxidation mechanism of (Zr_0.25Ti_0.25Nb_0.25Ta_0.25)B₂ high-entropy diborides (HEB₂-1) is investigated by first-principles calculations at the atomic level. By employing the two-region model method, the most stable surface of HEB₂-1 is determined to be (110) surface. The dissociative adsorption process of the oxygen molecule on the HEB₂-1-(110) surface is predicted to proceed spontaneously, where OO bond breaks and each oxygen atom is chemisorbed on the most preferable hollow site. The adsorption energy and the diffusion barrier of the oxygen atom on the (110) surface of HEB₂-1 are in the vicinity of the average level of the corresponding four individual diborides. In addition, ab initio molecular dynamics simulations indicate a high initial oxidation resistance of HEB₂-1 at 1000 K. Our results are beneficial to further designing the high-entropy diborides with excellent oxidation resistance.

Ultrafine-grained (Sm_0.2Gd_0.2Dy_0.2Er_0.2Yb_0.2)₂Zr₂O₇ high-entropy zirconates with single fluorite structure have been fabricated by high-pressure sintering of the self-synthesized nanopowders for the first time. The as-sintered samples exhibit a good microstructure with a grain size of 220 nm and a relative density of 96.8%, which yield excellent comprehensive mechanical properties with a high Vickers hardness of 12.5 GPa and a high fracture toughness of 3.4 MPa·m^1/2. In addition, the as-sintered samples possess a good thermostability with the grain growth rate of 30 nm/h, and a low thermal conductivity of 1.57 W·m⁻¹·℃⁻¹ at room temperature. The superior mechanical and thermal properties are primarily attributed to the “high-entropy” and grain-refinement effects and good interface bonding.

The high-purity and superfine high-entropy zirconate nanopowders, namely (Y_0.25La_0.25Sm_0.25Eu_0.25)₂Zr₂O₇ nanopowders, without agglomeration, were successfully synthesized via polymerized complex method at low temperatures for the first time. The results showed that the crystallinity degree, lattice strain, and particle size of the as-synthesized powders were gradually enhanced with the increase of the synthesis temperature from 800 to 1300 ℃. The as-synthesized powders involved fluorite phase in the range of 800-1200 ℃ while they underwent the phase evolution from fluorite to pyrochlore at 1300 ℃. It is worth mentioning that the as-synthesized powders at 900 ℃ are of the highest quality among all the as-synthesized powders, which is due to the fact that they not only possess the particle size of 11 nm without agglomeration, but also show high purity and good compositional uniformity.

High-entropy nanomaterials have been arousing considerable interest in recent years due to their huge composition space, unique microstructure, and adjustable properties. Previous studies focused mainly on high-entropy nanoparticles, while other high-entropy nanomaterials were rarely reported. Herein, we reported a new class of high-entropy nanomaterials, namely (Ta_0.2Nb_0.2Ti_0.2W_0.2Mo_0.2)B₂ high-entropy diboride (HEB-1) nanoflowers, for the first time. Formation possibility of HEB-1 was first theoretically analyzed from two aspects of lattice size difference and chemical reaction thermodynamics. We then successfully synthesized HEB-1 nanoflowers by a facile molten salt synthesis method at 1423 K. The as-synthesized HEB-1 nanoflowers showed an interesting chrysanthemum-like morphology assembled from numerous well-aligned nanorods with diameters of 20-30 nm and lengths of 100-200 nm. Meanwhile, these nanorods possessed a single-crystalline hexagonal structure of metal diborides and highly compositional uniformity from nanoscale to microscale. In addition, the formation of the as-synthesized HEB-1 nanoflowers could be well interpreted by a classical surface-controlled crystal growth theory. This work not only enriches the categories of high-entropy nanomaterials but also opens up a new research field on high-entropy diboride nanomaterials.