Given the widespread use of nuclear energy, shielding materials must exhibit superior radiation attenuation, mechanical strength, and corrosion resistance. Traditional materials often fall short in complex environments. In this study, a double-layered nuclear shielding composite was fabricated via powder metallurgy. The inner layer is a CrB2 ceramic particle@borated stainless-steel nuclear shielding composite with high wear and corrosion resistance, while the outer layer is bonded with a 316 stainless-steel plate to enhance toughness. The results show that the composite with 10 vol% CrB2 particles exhibited excellent performance. During sintering, partial dissolution of CrB2 particles occurred, with diffusion B atoms forming NbB, MoB, and (Fe, Cr)2B borides. A wetting layer (about 44 mu m) between particles and matrix was formed, consisting of CrB, (Cr, Fe)B, and (Fe, Cr)2B. The CrB phase exhibited the highest nanohardness (51.02 GPa) and Young's modulus (493.618 GPa). According to EBAD theory, the composite can achieve 99% theoretical neutron shielding with a thickness of only 0.79 cm when the 10 vol% CrB2 particles. Moreover, its corrosion resistance in a 1.5 wt% H3BO3 + 100 ppm Cl- environment remained comparable to that of the matrix. With only 10 vol% CrB2 addition, the wear mass loss was notably reduced to 0.1911 g, which is only 16.68% of that of the 3-1 sample and 31.32% of the Cr16 sample. The 316 stainless-steel plate outer layer significantly improved impact toughness: the toughened composite reached 18.89 J/cm2, approaching that of 316 stainless-steel (22.40 J/cm2) and far exceeding the untoughened composite (3.07 J/cm2).

In rotary hearth furnaces, the service life of spiral blades is determined by their high-temperature wear resistance. This study developed a Cr3C2 ceramic particle/heat-resistant stainless-steel composite that combines both wear resistance and high-temperature performance, specifically targeting the limitations of conventional rotary blades, including insufficient wear resistance, short service life, and high costs. During the sintering process, partial dissolution of Cr3C2 particles released C and Cr elements, which subsequently reacted with the metal matrix to form various carbo-borides, including M7C3-type carbides, MC-type carbides, M2(C, B)-type carboborides and M23(C, B)6-type carbo-borides. At room temperature, the composite with 25 wt% Cr3C2 demonstrated optimal wear resistance, achieving a hardness of 390.56 HV10 (2.36 times the matrix material) and reducing wear volume loss to 0.0425 cm3 (merely 29.07% of the matrix material, 0.1462 cm3). Additionally, small addition of Cr3C2 ceramic particles effectively improved high-temperature oxidation resistance. Composites with <= 20 wt% Cr3C2 exhibited superior high-temperature oxidation resistance compared to the matrix and reference sample Cr16. The optimal 15 wt% Cr3C2 composite formed the thinnest oxide layer (2 mu m), consisting primarily of Cr2O3, Fe2O3, FeCr2O4, and NiFe2O4. Under high-temperature wear conditions at 800 degrees C, the composite containing 25 wt% Cr3C2 again demonstrated the optimal performance, exhibiting an average friction coefficient of 0.5658 and a wear scar width of 393 mu m. In practical applications, the Cr3C2 ceramic particles/ heat-resistant stainless-steel composites demonstrated exceptional performance at 1200 degrees C, achieving 6.7 times longer service life than conventional Cr28Ni20W20 materials in mixer screw blades.

In order to verify the nitriding layer thickening effect of the intermediate annealing-twice nitriding process and to further study the related mechanism, continuous twice nitriding and intermediate annealing-twice nitriding treatments with different process parameters were carried out on pure iron. The thickness of the nitriding layer of the sample intermediate annealing-twice nitriding at 580 °C for 2 h was significantly increased. The compound layer thickness increases by 67.3% compared to the once nitriding sample, and the nitriding layer thickness increases by 69.5%, reaching 101.04 μm. The electron backscatter diffraction (EBSD) results indicate that the surface phase structure of the sample transforms from Fe2-3N to Fe4N after intermediate annealing, which provides favorable conditions for the twice nitriding process. Microhardness tests show that the hardness decreases after intermediate annealing, which is attributed to the decomposition of nitrides and the inward and outward diffusion of active nitrogen atoms. The results of electrochemical and uniform immersion corrosion tests indicate that the thicker nitriding layer of the intermediate annealing-twice nitriding sample leads to better corrosion resistance. The corrosion weight loss of the sample intermediate annealing-twice nitriding at 580 °C for 2 h decreases by 0.6397 mm/a compared with the pure iron sample, and decreases by 20.4% compared with the once nitriding sample. These findings indicate that intermediate annealing can achieve nitrogen concentration redistribution in the nitriding layer, resulting in deeper nitriding layers and better corrosion resistance after twice nitriding. The mechanism and related issues during the intermediate annealing-twice nitriding process were analyzed via the X-ray diffraction (XRD) and transmission electron microscope (TEM) tests.

A facile route to architect gradient structure via manipulating chemical heterogeneity is presented. Such strategy is deployed in a commercial low-carbon steel via diffusion bonding process. The fabricated steel possesses a multi-gradient including variations in grain size, volume fraction and lamellar spacing of pearlite, induced by the gradient distribution of interstitial C-atoms. This microstructural gradient enables a gradient distribution of hardness and an excellent strength-toughness combination (yield strength of 603 MPa and toughness of 11.98 GPa center dot%), even comparable to high-performance steels fabricated by complicated processes. The high strength is attributed to the increased carbon content, which results in a higher volume fraction of pearlite. The superior toughness originates from the deformation accommodation and successive fracture mechanisms, transitioning from ductile fracture near the surface to brittle quasi-cleavage fracture at the center of the plates. This strategy is anticipated to apply to tailor structural gradient in other advanced metals for industrial-scale production.

To effectively regulate high temperature on the properties of the base materials and the surface decarburization of low carbon steel (LCS) caused by the violent atomic interdiffusion, low-temperature vacuum diffusion bonding technology was used via graphite interlayer eutectic reaction with steel. Tunning the hardness distribution of different layer to improve the strength and ductility of 304 stainless steel (304SS)/LCS composite material by an in-situ eutectic reaction. Achieved a strong metallurgical bonded interface layer which consist of pearlite, austenite and M7C3 carbide eutectic structure. As a result, the tensile test perpendicular to the interface shows that the yield strength, tensile strength and total elongation of 304SS/LCS composite material are 256 MPa, 419 MPa and 22 %, respectively. The tensile fracture location at LCS layer, demonstrating the superior mechanical properties of the interface layer and the strong metallurgical bonding between 304SS and LCS. This study presents an effective solution for achieving reliable bonding between 304SS and LCS, which can be used for vacuum diffusion bonding of stainless and carbon steels due to its beneficial eutectic reaction.

Based on the synergistic effect of hybridisation-superhydrophobicity, a simple and facile spraying method was used to achieve efficient sealing of Fe-based amorphous metallic coatings. In this paper, we employed rare-earth neodymium salts as inorganic sealant raw materials and loaded low surface energy fluorosilanes into epoxy resins to act as organic sealant raw materials. The surface structure and chemical composition of the sealing coatings were systematically characterised. The sealing mechanism as well as the anti-corrosion mechanism of the coating were investigated intensively. The results indicate that the superior corrosion resistance and selfcleaning ability of the sealed coating stems from the inorganic-organic-complex trinity effect: the corrosion inhibition effect of Nd oxide deposited during the inorganic sealing process, the shielding effect of the resin in the organic sealing, and the cross-linking and superhydrophobicity behaviour (liquid repellency effect) of the FDTESNd3+-Fe2+ complexes formed on the surface of the coating. This work provides valuable guidelines and insights for the design of subsequent corrosion-resistant and sealing coating.

Photothermal superhydrophobic surfaces, as one of the most promising anti-icing strategies, often suffer from significant performance degradation, such as loss of hydrophobicity and lack of mechanical durability under actual icing conditions, as well as in special environments. Also, under mechanical loading, abrasion exposes the underlying material, which alters the wettability of the surface from hydrophobic to hydrophilic. Here, we prepared a robust photothermal superhydrophobic coating with excellent environmental durability. The amorphous coating acts as an armor structure to resist abrasion, preventing the inner photothermal superhydrophobic filler from being abraded by abrasives larger than the frame size. The results demonstrate excellent water resistance (WCA: 158.2°) and photothermal conversion (1 sun irradiation: surface temperature rises up to 76.6 °C), significant icing delay, and fast ice melting behavior. The anti/deicing behavior is derived from the stable superhydrophobic surface, the excellent photothermal conversion of GO, and the competitive effect of hydrogen bonding between the oxygen-containing functional groups at the edge of GO with water molecules, further improving the anti-icing performance. Furthermore, the reliability of the coating was verified by a comprehensive durability assessment, including resistance to abrasion, acid and alkaline environments, temperature, water impact, and corrosion. This work offers great potential for the fabrication of photothermal superhydrophobic surfaces that are low-cost, efficient, durable, and convenient for large-scale preparation.

Conventional single-metal materials fail to withstand increasingly complex wear conditions. Although hybrid ceramic-reinforced metal matrix composites exhibit superior properties, existing studies predominantly focus on their microstructure and wear resistance. In this paper, ZTA (Zirconia-Toughened Alumina) + Cr3C2 hybrid ceramic particles/Ni-hard-HCCI (High Chromium Cast Iron) composites were prepared by the powder metallurgy method, tested for microstructure, hardness, wear resistance and high-temperature oxidation resistance. The composites were applied to industrial manufactured roller sleeves. The results showed that the ceramic particles were well combined with the matrix. Cr3C2 ceramic particles formed a 20 mu m interfacial layer with the matrix, which was rich in Cr and C. ZTA particles formed a 5-10 mu m interfacial layer with the matrix. During sintering, the elements Fe, Mn, Cr, Si, Al and O interacted to form new phases, including (Al, Cr)2O3, (Al, Mn, Ni), (Fe, Mn)2SiO4, (Al, Cr)2O3, (Mn, Fe)SiO3 and Al2Fe3(SiO4)3. Notably, Si-Zr mutual attraction created Zr-enriched/Aldepleted banded microzones at wetting layer boundaries. During wear, ZTA ceramic particles primarily bore the abrasive load, while Cr3C2 ceramic particles enhanced the matrix strength, collectively improving the wear resistance. The average wear mass loss of hybrid ceramic particles samples (0.076 g) was 64.41 % of the 20 wt% Cr3C2 samples (0.118 g). The hybrid ceramic particles composites have excellent high-temperature resistance. In industrial roller sleeve applications, the service life of the new composite materials was 1-2 times longer than that of traditional HCCI wear-resistant materials.

To address the challenge of increasing the thickness of the nitriding layer, an intermediate annealing-twice nitriding process was applied to pure iron, and the corrosion resistance of the nitriding samples was investigated. After the intermediate annealing-twice nitriding treatment, the thickness of the compound layer in the sample increased by 84 % compared to once nitriding, reaching 48.14 mu m, while the transition layer thickness increased by 57 % to 52.49 mu m. The intermediate annealing process at 600 degrees C for 1 h yielded a superior twice nitriding effect. And the intermediate annealing-twice nitriding process resulted in a significantly thicker nitriding layer compared to simple twice nitriding. The phase transformation and thickening mechanism of the nitriding layer during the process were revealed by EBSD, XRD, and TEM. Electrochemical tests showed that the nitriding samples exhibited repeated passivation behavior, and the sample with a thicker compound layer demonstrated better corrosion resistance.

Gas nitriding is a common method of surface modification, in which the thick nitriding layer in austenite region is favored by industrial production. To comprehensively analyze the microstructure, phase composition, diffusion kinetics and microhardness of nitriding samples, the gas nitriding experiment of industrial pure iron in austenite region was carried out. It has found that the diffusion coefficient of N increases with temperature, leading to an increase in the thickness of the nitriding layer. However, the formation of pores is observed at 680 degrees C, so the optimal nitriding process was identified as 660 degrees C for 3 h, resulting in a nitriding layer thickness of 62.13 mu m. After nitriding, due to the presence of nitriding layer and the solid solution strengthening effect of N, the surface hardness of the sample increased by nearly seven times, reaching 697.61 HV0.025.

Enhancing the bond strength between WC-Co and steel is crucial for broadening its applications. In this study, WC-Co was bonded to low-carbon steel (LCS) using a Ni-Fe-Cr alloy at 1180 degrees C in an argon atmosphere furnace. The WC-Co/LCS (WL) interface was characterized by XRD, SEM, and EPMA, revealing no cracks or pores and confirming robust metallurgical bonding. The bonded material's shear strength reached approximately 321-328 MPa, significantly exceeding that achieved with Ag-Cu-Zn-Cd, Cu-Zn, Cu-Ni-Al, Ag-Cu-Zn + Ni/Mn, and Ag-Cu-In-Ti filler materials in the welding process. EPMA analysis showed that Fe, Cr, and Ni from the Ni-Fe-Cr alloy diffused into the WC-Co over distances of approximately 802-815 mu m, 803-817 mu m, and 632-641 mu m, respectively. Initially, WC decomposed at sharp corners to form WIC, which subsequently reacted with Fe and Cr to form M6C and M7C3. This methodology was also applied to producing roller sleeves for vertical mills, increasing their lifespan by 1.9 times.

High chromium irons(HCI) have rarely been investigated the impact of varying W content on the microstructure and performance of high-carbon irons by scholars. In this study, after calculating by Java-based Materials Properties software (JMatPro), the casting alloying method was applied to explore the effect of adding W (0-15wt.%), Mo 3wt.%, and C 6wt.% on HCI to prepare highly wear-resistant and hard materials. The results showed that the maximum volume fraction of carbide was 38% at C 6wt.%. The addition of W promoted the formation of M6C with a maximum volume fraction of 21%, which increased the hardness to 64.5 HRC and reduced the weight loss to 0.062 g. Since W10 (the iron with W 10wt%) and W15 (the iron with W 15wt%) exhibited similar wear resistance but lower impact resistance, the W10 samples were heat-treated. W10 after QT550 (quench and temper heat treatment at 550°C) sample developed a large number of M6C-type carbides and martensite in the matrix, which improved the properties of the matrix by diffusion strengthening, leading to a hardness of 70.0 HRC and a reduction in weight loss to 0.035 g. Compared to the Cr20 reference iron, W10 after QT550 was 22.8% higher in hardness and 76.8% lower in abrasion. Concurrently, an experiment was conducted on the production of roller sleeves. With the use of W10 after QT550, the lifetime of the roller sleeve was increased by 1.6 times.

Millimeter-sized ZTA (zirconia toughened alumina) particles + WC (tungsten carbide) particles reinforced hypereutectic high chromium cast iron (H-HCCI) composites were prepared by liquid phase sintering. The volume fraction, stacking method and sintering process of the reinforced particles in the composites were designed. The interfacial bonding mechanism between the reinforcements and the matrix in the composites was systematically discussed. The results show that when the sintering temperature is 1380 °C, the volume percentage of ZTA particles, WC particles and H-HCCI is set to 10, 30 and 60

A novel heterogeneous structure welded joint was developed by joining low carbon steel (LCS) with hypereutectic high -chromium white cast iron (HCWCI). The tensile strength and ductility of LCS are 470.3 MPa and 25.3%, while that of HCWCI are 460.5 MPa and 1.6%, respectively. Additionally, tensile test results show that the welded joint exhibited the superb synergy of the tensile strength of 445.6 MPa and the ductility of 12.5%. These achievements can be primarily attributed to the presence of multi -level deformation mechanisms resulting from the heterogeneous structures. The study also investigated the impact of microstructural changes in the diffusion zone after postweld heat treatment (PWHT). The findings reveal that the reduction in hardness and tensile strength is mainly due to the transformation of carbides in the diffusion zone. This research sheds light on the potential of employing heterogeneous structures in welded joint, serving as a valuable guide for optimizing the mechanical performance of a broad spectrum of alloys in lightweight engineering applications.

Liquid-state bonding is one of the most crucial methods in joining dissimilar materials to manufacture composites with structural design. The high chromium gray cast iron (HCGCI)/low carbon steel (LCS) composite structure is attractive in mining industries due to its superior mechanical properties and low density. However, the decarburization of the faying surface of HCGCI leads to the formation of a coarse-grained brittle interlayer between HCGCI and LCS which seriously deteriorates the mechanical properties of welded joints. In this work, high chromium gray cast iron/low carbon steel composite was fabricated by diffusion bonding via graphite coating layer. The results showed that the graphite coating on the fusion surfaces prevented the decarburization of HCGCI and the growth of coarse grains which improved the bonding quality. The ultimate tensile strength and total elongation of the graphite-free sample are 335.6 MPa and 8.9%, respectively. In contrast, the ultimate tensile strength and total elongation of the graphite-contain sample are 435.6 MPa and 17.9%, separately. This work opens a new strategy for fabricating high chromium gray cast iron/low carbon steel composite, and the flexibility to achieve complex structures through liquid-state bonding is extended.

In this paper, mixed powders containing Ti(C, N), Fe, Mo, and Cr were combined with a low carbon steel (LCS) plate by heating to 1723 K in an argon-protected furnace and holding for 30 min to form a metallurgical bonding layer at the interface. By SEM and EPMA, it was observed that there were neither pores nor other defects at the interface. In Ti(C, N)–Fe/LCS (TFS), the Ti(C, N)–Fe (TF) side consists mainly of Ti(C, N), and the main particle morphology was round; however, there were some cyclic and semicyclic Ti(C, N) particles produced by dissolution, and the reprecipitation of fine particles along the austenite grain boundaries was observed during the sintering process. Moreover, Mo was polarized at the interface between Ti(C, N) particles and the steel matrix, forming a Mo-containing interfacial compound layer and improving the wettability of the interface between Ti(C, N) and the matrix. At the interfacial bonding surface of the TF and LCS, the direction and speed characteristics of the growth of the grains were different, leading to the present square and triangular diagrams of Ti(C, N). The diffusion distances of Cr and Ni in the LCS were approximately 35∼45 μm and 40–50 μm, respectively. The shear strength of the composite interface measured by a universal testing machine and a homemade mold was 245 MPa, which was better than the brazing strength. Compared with TF, the tensile strength of TFS was 50.2 % higher, and the bending strength was 63.5 % higher.

The hot compression simulation testing machine was utilized to conduct compression experiments on an Al-Mg-Si-Mn alloy containing the rare earth element Sc at a deformation temperature ranging from 450 to 550 °C and a strain rate of 0.01 to 10 s−1. The study focused on the hot deformation behavior of the aluminum alloy, resulting in the determination of the optimal range of deformation process parameters for the alloy. The relationship between material flow stress, deformation temperature, and strain rate was described using the Arrhenius relationship containing thermal activation energy based on the stress-strain curve of hot compression deformation of aluminum alloy. This led to calculations for structural factor A, stress index n, and stress level parameters as well as thermal deformation activation energy to establish a constitutive Formula for hot deformation rheological stress of aluminum alloy and calculate the power dissipation factor η. Through this process, an optimized range for the optimal deformation process parameter for aluminum alloy was determined (deformation temperature: 490~510 °C; strain rate: 0.05 s−1) and verified in combination with mechanical properties and microstructure through hot extrusion deformation trial production.

In the long-term use of high manganese steels, it is not desirable to achieve wear resistance by austenite deformation strengthening alone. The wear resistance of high manganese steel is much lower than that of ordinary wear-resistant steel under medium and low stress conditions. Improving the instability of wear resistance caused by defects in high manganese steels is an important problem to be solved in current industrial production. In this study, a new type of high manganese alloy with high hardness and high wear resistance was prepared by multi-alloying with Cr-W-Mo elements on the basis of 20Mn1.2C. ZTA ceramic particles reinforced high manganese steel composites were prepared by selecting high manganese steel materials with excellent mechanical properties as the metal matrix of ceramic reinforced metal matrix composites. The Cr-W-Mo multi-alloyed high manganese alloys are mainly composed of a mixed austenite and ferrite matrix, M3C-type cementite and M6Ctype carbides. The Cr2W6Mo6 sample has the best overall mechanical properties. Its hardness reached 49.8 HRC, which is 1.20 times higher than that of the Cr2 sample. The mass loss was 0.2571 g, which is 79.92% of the Cr16 sample (0.3217 g). The ZTA ceramic particles were well composited with the alloyed high manganese steel matrix, and the thickness of the interfacial layer was 20-30 mu m, with the formation of Mn2AlO4 and (Fe, Mn)2SiO4, and (Al, Cr)2O3 in the interfacial layer. The best abrasion resistance was obtained at a ZTA content of 40 vol%. The mass loss was 0.1669 g, which is 51.88% of the Cr16 material (0.3217 g).