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Damping alloys can dissipate vibration energy into thermal energy through defective motion with high mechanical properties and functional characteristics， which have a great significance in the development and research of aerospace and military fields. There are differences in microstucture between different alloy systems. The types of defects that play a dominant role in damping are different， and the properties of structureal defect （type， density， and movability） are the key factors affecting the damping performance of alloys. The types and characteristics of damping source for different damping alloys systems were summarized from the perspective of defects （plane defects， line defects， and point defects）. The relationship between damping capacity， mechanical properties， and functional properties （corrosion resistance， casting performance， etc.） was reviewed， the development status of various damping alloys was summarized， and then the development laws and differences of damping alloys were concluded. Finally， the research direction of damping alloys is prospected. The single type of damping source will seriously limit the improvement of the material damping capacity. While the design concepts of composite materials and high-entropy alloys allow for the coexistence of multiple damping sources， which produces the coupling effect of multiple damping mechanisms that can realize the two-dimensional expansion of damping capacity， and improve mechanical properties and functionalities. The design concepts will play a significant guide to enhance comprehensive performance of damping alloys.

The composition of high-damage-tolerance dual-phase TC21 (Ti-6Al-2Zr-2Sn-2Mo-2Nb-1.5Cr) were analyzed on the basis of the dual-cluster formula of Ti-6Al-4V, consisting of 13 α-Ti and 4 β-Ti unit. Its β-Ti unit is reduced from 5 to 4 compared with Ti-6Al-4V, while adding more β-stabilizing elements to enhance the strength and plasticity. Subsequently, the atoms of each β-stabilizing element within the β-Ti cluster formula of TC21 were proportioned equally to increase the mixing entropy, and more Zr content was increased to substantially enhance the β-phase stability, giving the cluster formula as α-{[Al-Ti12](AlTi2)}13+β-{[(Al-(Ti12Zr2)]Sn0.75Mo0.75Nb0.75Cr0.75}4(atom fraction), named as TC21Z2, with the corresponding mass fraction of Ti-5.9Al-5.4Zr-2.6Sn-2.1Mo-2.0Nb-1.1Cr. The samples were prepared by using vacuum copper mold pouring process and the as-cast microstructure and tensile mechanical properties of the alloy were studied.Results show that the as-cast microstructure of TC21Z2 is composed of α+α' martensite+ a small amount of β phases, and its ultimate tensile strength, yield strength and elongation are 1289, 1181 MPa and 1.4%, respectively. Its strength and plasticity are better than those of the TC21 at the same state.

As a new material system, the high entropy ceramics have become a hot research topic in the field of materials because of their unique and adjustable properties benefited by the huge component space, unique microstructure and large configuration entropy. The research of the high entropy ceramics is still in the initial stage at present, especially for the accurate composition design theory, preparation of high purity and high conversion powder, new sintering process and other aspects, which need to be further explored. Therefore, the five high entropy effects, new design theory, powder preparation methods, new sintering methods, comprehensive properties and practical applications of high entropy compounds ceramics were sorted and summarized, the composition design of high entropy ceramics (HEC) by the cluster-plus-glue-atom model (CPGA) was analyzed, and the relationship between the components, microstructure, and performance of HEC was explored deeply. The key development direction of future HEC will still be basic theoretical design, especially for the composition and structure of non oxide HEC. At the same time, the breakthroughs in interdisciplinary fields was sought, such as using artificial intelligence machine learning and 3D printing for sample preparation. Finally, the practical applications in structures, thermal barrier and corrosion resistant coatings, machinery, engineering optics, and magnetism were searched, and the strengthening and failure mechanisms were explored and analyzed in-depth under the investigated working environment.

Aiming at improving the strength-plasticity match in the as-cast state of the most widely used Ti-6Al-4V the present work designs Ti-Al-V-Zr alloys on the basis of the dual-cluster formula of Ti-6Al-4V, α-{[Al-Ti12]（AlTi2）}12 +β-{[Al-Ti14]（V2Ti）}5： first, the alloys are more biased towards α-Ti by decreasing the number of β unit to 2, then, the stability of β-Ti is improved by increasing the number of V atoms in β unit to 3, and finally, Zr （x=1-5） replaces Ti in the β unit. Finally α-{[Al-Ti12]（AlTi2）}15-β-{[AlTi14-xZrx]V3）}2 is obtained, Ti-（6.64-6.82）Al-（2.42-2.35）V-（1.44-7.02）Zr （mass fraction,%） alloy is designed. The alloy ingots are prepared by melting in a non-consuming vacuum are furnace, and the alloy bars are suction-cast in copper mould. The results show that the alloys are all in α' martensite structure, showing morphologies changing from acicular Widmannstatten structure at lower Zr contents to net-basket structure at higher Zr contents. Among the designed alloys, Ti-6.64Al-2.35V-7.02Zr （x=5） with a net-basket structure, has the best mechanical properties： yield strength of 806 MPa, tensile strength of 963 MPa, and elongation of 5.9%, which are respectively 23%, 19% and 51% higher than those of Ti-6Al-4V alloy under the same preparation condition. In particular, the specific strength and specific hardness are 217kN•m/kg and 0.71 GPa•cm3/g, which are 18% and 10% higher than Ti-6Al-4V alloy.

Thermal protection system (TPS) is of great significance to launch hypersonic flight and landing process of hypersonic vehicles, which can effectively shield the hypersonic vehicle from severe aerodynamic heating encountered. Phenolic aerogels play an important role in TPS due to their characteristics of low density, high porosity, and low thermal conductivity. However, phenolic aerogel is easy to be oxidized at elevated temperatures under oxidizing environments, which severely limits its large-scale application as thermal insulation materials in TPS. In this study, a novel TiB2–B4C/carbon (TB/C) aerogel composite was synthesized by introducing TiB2 and B4C particles into phenolic aerogels through quick-gelation and mechanical mixing. The developed aerogel composites were characterized by scanning electron microscopy, Fourier transform infrared, thermal analysis, etc., to evaluate their microstructure, oxidation resistance, and mechanical properties. Experimental evidence showed that TiB2 and B4C particles reacted with the oxygen-containing molecules to form TiO2–B2O3 layer, which effectively improved oxidation resistance and mechanical properties of phenolic aerogel composites.

Soft magnetic materials have been widely applied in modern industries as energy materials. In recent years, with the increasingly high frequency and miniaturization of magnetic components, as well as the call of energy conservation and environmental protection, the development and research of high-performance soft magnetic material are of great important significance. The present work generalized the development history of soft magnetic alloys comprehensively, from the viewpoints of chemical compositions, microstructures, magnetic properties, application fields, and advantages and disadvantages of different soft magnetic alloys. The involved alloy systems include primarily traditional crystalline alloys, amorphous/nanocrystalline alloys, and high entropy alloys. It is found that the microstructure induced by alloy compositions plays a dominant role in soft magnetic property, especially the coercivity. Then the influence factors on the coercivity of alloys and the related micro-mechanisms were discussed, in which the grain size in traditional alloys or particle size in nano-crystalline alloys is crucial to achieve lower coercivity. Therefore, the development of the micro-mechanisms of coercivity in high entropy soft magnetic alloys was described. Finally, it was expected that high entropy soft magnetic alloys would be more beneficial to modulate alloy properties due to the diversification of microstructures induced by the mixing of multi-principal elements, which shows great potential to serve as a new generation of high temperature soft magnet materials.

Abstract Background Hematoma expansion is an independent predictor of patient outcome and mortality. The early diagnosis of hematoma expansion is crucial for selecting clinical treatment options. This study aims to explore the value of a deep learning algorithm for the prediction of hematoma expansion from non-contrast computed tomography (NCCT) scan through external validation. Methods 102 NCCT images of hypertensive intracerebral hemorrhage (HICH) patients diagnosed in our hospital were retrospectively reviewed. The initial computed tomography (CT) scan images were evaluated by a commercial Artificial Intelligence (AI) software using deep learning algorithm and radiologists respectively to predict hematoma expansion and the corresponding sensitivity, specificity and accuracy of the two groups were calculated and compared. Comparisons were also conducted among gold standard hematoma expansion diagnosis time, AI software diagnosis time and doctors’ reading time. Results Among 102 HICH patients, the sensitivity, specificity, and accuracy of hematoma expansion prediction in the AI group were higher than those in the doctor group(80.0% vs 66.7%, 73.6% vs 58.3%, 75.5% vs 60.8%), with statistically significant difference (p