Polyimide aerogel （PIA） possesses excellent thermal stability， remarkable mechanical properties， and good dielectric performance， etc.， and is extensively applied in domains such as aerospace， electronic communication， and adsorption cleaning. Nevertheless， the high shrinkage rate and inferior hydrophobic performance of PIA significantly impact its practical application. Herein， This study meticulously design the molecular structure of polyimide and integrates it with a composite filling process to fabricate a composite aerogel characterized by a low shrinkage rate and superior hydrophobicity. This innovative material is specifically tailored for efficient oil-water separation， aiming to enhance the anti-shrinkage and hydrophobic characteristics of polyimide aerogels （PIA）. ACF/PIA-10 has superior dimensional stability （with the shrinkage up to 12.7%）， high mechanical properties （with the compression strength up to 2.36 MPa），outstanding moisture resistance （with the contact angle up to 111°） and excellent thermal stability （with T_5% up to 519 ℃ in nitrogen）. The addition of activated carbon fibers not only enhances the mechanical properties of the material but also optimizes its pore structure. The composite aerogel exhibits a high adsorption capacity for oils， which makes it have considerable application prospects in the field of adsorption cleaning.

Graphene aerogel，with its advantages of low density，high porosity，and a substantial specific surface area，holds promise for diverse applications in oil absorption. In this study，we employ ethylenediamine chemical grafting and a hydrothermal technique to synthesize graphene aerogel. To further refine its structure，carbon nanotubes （CNTs） are grown within the aerogel matrix using chemical vapor deposition. Subsequently，an octadecylamine surface treatment is applied further to enhance the oil absorption capacity of the material. We conduct a comprehensive investigation of the chemical composition，micromorphology，phase composition，and oil absorption properties of the prepared graphene aerogel material. The results reveal that the formability of the graphene aerogel is significantly influenced by the concentration of graphene oxide and the amount of ethylenediamine. Moreover，following structural optimization and surface modification，the oil absorption capability of the graphene aerogel increases dramatically. The modified three-dimensional graphene aerogel exhibits exceptional oil absorption capacity，with an adsorption capacity of up to 98.2 g·g^-1 and an adsorption flux of 9.98×10⁴ L·m^-2·h^-1. The technological insights obtained from this work will serve as a valuable reference for developing high-performance 3D graphene oil-absorbing materials. The results of this study offer a promising technical foundation for advancements in this field.

As critical equipment capable of replacing firefighters in fire suppression and rescue operations， firefighting robots have garnered increasing attention， with intelligence and autonomy becoming major developmental trends. However， such robots face significant challenges in complex thermal environments during firefield operations， where core control components and sensors for autonomous functionality are at risk of thermal failure. Thus， highly efficient and reliable thermal protection materials and technologies are essential to ensure stable robot performance. This paper focuses on thermal protection for firefighting robots， reviewing key materials including thermal protection coatings， thermal insulating materials， and phase-change energy storage materials， while systematically analyzing research progress in integrated thermal protection strategies and critical component protection design. Current limitations are summarized， particularly the trade-off among high-temperature resistance， lightweight properties， long-term stability issues， and cost constraints. Future research directions are proposed， emphasizing intelligent thermal protection systems， sensor integration with data fusion， and dynamic thermal management， aiming to advance the engineering applications of firefighting robots.

Al₂O₃-ZrO₂-based eutectic ceramics，fabricatedby rapid solidification technology and composed of ultrafine，three-dimensionally intertwined single-crystal domains，represent a distinct category of eutectic oxides. These materials exhibit exceptionally high-temperature mechanical properties，such as strength，toughness，and creep resistance when aligned along the preferred growth direction，rendering them preferred ultrahigh-temperature structural materials for long-term operation in high-temperature oxidizing atmospheres. This paper comprehensively reviews the eutectic systems，advanced preparation techniques，microstructure characteristics，and mechanical properties of Al₂O₃-ZrO₂-based eutectic ceramics，with particular emphasis on their high-temperature mechanical performance. It begins by summarizing the material systems of Al₂O₃-ZrO₂-based eutectic ceramics developed to date，followed by a concise introduction to the basic principles，advantages，limitations，and application areas of their advanced preparation technologies. Finally，a detailed comparative analysis is provided，highlighting the typical microstructures and high-temperature mechanical properties-including creep resistance and flexural strength-of Al₂O₃-ZrO₂-based eutectic ceramics prepared by advanced processes. Compared to traditional eutectic ceramics，Al₂O₃-ZrO₂-based eutectic ceramics fabricatedby rapid solidification technology，characterized by unique microstructures and superior mechanical properties，not only enhance the performance and preparation efficiency of conventional sintered oxide materials but also demonstrate unprecedented potential for applications in extreme environments involving high temperatures，high pressures，and strong oxidation.

Performance metal powder serves as a crucial material in 3D printing additive manufacturing， as the properties of the powder directly influence the microstructure and overall performance of 3D-printed components. The plasma rotating electrode process （PREP） employs high-temperature plasma to melt the end face of a rapidly rotating electrode rod. Subsequently， the molten liquid film is fragmented into droplets， which then solidify into powder under the action of centrifugal force. This paper provides a comprehensive review of the development history， equipment types， powder preparation principles， and performance characteristics of the PREP process. It also delves into the impact of process parameters on the powder's properties and discusses the application of numerical simulation methods in understanding the powder formation mechanism and controlling powder particle size. Furthermore， the paper reviews the progress made in applying PREP-prepared powder materials in the 3D printing manufacturing of aerospace， medical equipment， nuclear power， rail transit， and other equipment sectors. Finally， it is highlighted that the PREP milling process is poised to evolve towards higher purity， finer particle size， narrower particle size distribution， fewer inclusions， higher sphericity， greater efficiency， and lower costs.

To delve into the impacts of multiple brazing thermal cycles at varying peak temperatures on the microstructure and properties of GH4169 alloy， this study conducted a comprehensive examination of how brazing thermal cycle processes influence the precipitates， grain size， tensile properties， and stress-rupture properties of the alloy.The findings reveal that as the thermal cycle temperature rises， the quantity of δ-phase precipitation diminishes， and its morphology undergoes a transformation from needle-like to rod-like and eventually to granular. Within the temperature range of 970-1010 ℃， the grain size experiences minimal alteration. However， when the temperature surpasses 1020 ℃， significant grain growth occurs. Both tensile strength and hardness initially ascend and then descend with an increase in the thermal cycle temperature， reaching their peak values at 1010 ℃. This phenomenon is mainly attributed to the dissolution of an appropriate amount of δ phase and the complete precipitation of γ″ and γ′ strengthening phases at this temperature， while the grain size does not show significant coarsening.The room-temperature impact toughness demonstrates distinct trends across different thermal cycle ranges. In the 970-990 ℃ range， it decreases with rising temperature due to the partial transformation of the δ-phase morphology from needle-like to rod-like. In the 990-1010 ℃ range， it increases with temperature as the δ phase dissolves and the strengthening-phase-free zone vanishes. Nevertheless， a further increase in the thermal cycle temperature leads to a reduction in toughness because of grain growth.The stress-rupture life initially declines and then rises with an increase in the thermal cycle temperature， hitting its lowest point in the 990-1000 ℃ range. This is caused by the partial transformation of the δ-phase morphology from needle-like to rod-like， which promotes microvoid nucleation and reduces the alloy's creep resistance. When the temperature further rises above 1020 ℃， the extensive precipitation of γ″ strengthening phases， along with significant grain growth， substantially enhances the alloy's creep performance. However， the substantial decrease in the needle-like δ-phase content results in increased notch sensitivity.Taking into account both mechanical properties and notch sensitivity， it is recommended to employ brazing thermal cycles around 1010 ℃ to achieve a well-balanced combination of strength and stress-rupture performance. For service environments with higher notch sensitivity requirements， a thermal cycle temperature in the range of 970-980 ℃ can be selected to minimize the risks of creep failure.

To tackle the issue of microstructural segregation in nickel-based alloy weldments and the consequent degradation of joint mechanical properties， this study delves into the impacts of two post-weld heat treatment schedules on the microstructural features and mechanical behavior of gas tungsten arc-welded Incoloy 825 nickel-based alloy joints.The results reveal that both heat treatment procedures lead to a notable coarsening of fine grain boundary carbides in the base metal （BM）. Moreover， the γ′ phase can be precipitated within BM grains through solution treatment combined with two-stage aging. Both post-weld heat treatments facilitate extensive precipitation of the δ and Laves phases in the WZ interdendritic zones， effectively alleviating segregation. Nevertheless， joints subjected to solution treatment and two-stage aging develop microcracks at the interface between the unmixed zone （UMZ） and the heat-affected zone （HAZ）， along with the formation of micropores within the HAZ. Mechanical characterization indicates a substantial increase in microhardness in the weld zone （WZ） after both heat treatment protocols. Solution treatment with single-stage aging maintains hardness levels in the HAZ and BM that are comparable to those in the as-welded state. Joints treated with solution treatment and single-stage aging show a marginal reduction in tensile strength， accompanied by a 9.2% improvement in uniform elongation， and fracture exclusively occurs within the BM. Conversely， the tensile strength of joints treated with solution treatment and two-stage aging significantly rises to 795 MPa， an increase of 17.3%， while the uniform elongation decreases. The fracture localization shifts to the UMZ/HAZ interfacial regions and adjacent HAZ areas， presenting a ductile-brittle mixed fracture morphology.

Aiming at the requirements for specifications and performance of GH3625 alloy seamless tubes used in novel renewable solar tower-type molten salt photothermal power generation absorbers， and addressing the shortcomings of the traditional hot extrusion technology—such as long production cycles， high energy consumption， and difficulties in producing billets with large length-to-diameter ratios—this study adopts the deep drilling method to replace traditional hot extrusion for preparing GH3625 alloy billets. Subsequently， Φ46 mm×4 mm×3000 mm and Φ44.45 mm×1.32 mm×9000 mm GH3625 alloy seamless tubes are manufactured through multi-pass cold rolling and intermediate annealing. EBSD analysis reveals that the grain size of the finished GH3625 alloy seamless tubes prepared by the deep drilling method is comparable to that of tubes produced by traditional hot extrusion technology. Moreover， the alloy microstructure contains a large number of annealing twin boundaries， which refine the grains. In addition， mechanical property test results indicate that the room-temperature and high-temperature properties of the finished GH3625 alloy tubes prepared by the deep drilling method are equivalent to those of tubes made by traditional hot extrusion technology. The room-temperature mechanical properties of both specifications meet the requirements of the ASME SB-444-2021 standard： tensile strength≥690 MPa， yield strength≥276 MPa， and elongation after fracture≥30%.

AA5052 aluminum alloy and 304 stainless steel with the thickness of 3 mm are welded with ZnAl22 flux-cored wire by tungsten inert gas （TIG） fusion-brazed welding. The effect of different welding currents and wire feeding speeds on the macro morphology of butt joints，microstructure of weld seam/steel interface，tensile properties and fracture behavior of the joints is studied. The results show that when the welding current is 110 A and the wire feeding speed is 24 mm/s，the maximum average tensile strength of the butt joints reaches 166 MPa. Fracture primarily occurs at the weld seam/steel interface， exhibiting typical brittle fracture characteristics. The weld seam/steel interface is composed of η-Fe₂Al₅Zn_0.4，η-Zn（Al） and α-Al. With the increase of the welding current，the tensile strength of the joint first increases and then decreases. The white granular δ-FeZn₁₀ appears in the η-Fe₂Al₅Zn_0.4 interfacial layer，and Zn elements are segregated at the η-Fe₂Al₅Zn_0.4/steel interface. The Zn-rich phases at the η-Fe₂Al₅Zn_0.4/steel interface are determined to be Γ-Fe₃Zn₁₀ by transmission electron microscopy. It is found that excessively high welding current leads to cracking at the η-Fe₂Al₅Zn_0.4/steel interface. With the increase of wire feeding speeds，the thickness of η-Fe₂Al₅Zn_0.4 decreases gradually，and the phase composition at the weld seam/steel interface remains unchanged. Based on thermodynamic analysis，it is concluded that the formation sequence of intermetallic compounds （IMCs） at the weld seam/steel interface is η-Fe₂Al₅Zn_0.4，δ-FeZn₁₀，Γ-Fe₃Zn₁₀.

Three different surface treatments—sandpaper polishing， chemical cleaning， and electrolytic polishing combined with chemical cleaning are employed to conduct hot compression bonding tests on 2024 aluminum alloy. The interface microstructure and the interface healing effect under different surface treatment conditions are investigated using characterization techniques such as OM，SEM， and EBSD. The results reveal that under the three surface treatment conditions， the types of interfacial oxide elements are identical， while variations exist in the quantity and size of the oxides. After holding for 4 h， second-phase particles within the matrix precipitate extensively along grain boundaries and at the bonding interface. For the sandpaper-polished specimen， oxides and second-phase particles at the interface account for approximately 32% of the interface area； this proportion is about 42% for the chemically cleaned specimen， and roughly 28% for the specimen subjected to electrolytic polishing combined with chemical cleaning. Interface healing is achieved through the synergistic action of discontinuous dynamic recrystallization and continuous dynamic recrystallization. Based on the microstructural characteristics of the bonding interface， the interface healing rate is utilized to evaluate the degree of interface healing. After statistical calculations， the order of the interface healing rate is as follows： electrolytic polishing combined with chemical cleaning>sandpaper polishing>chemical cleaning.