Developing advanced composites with high strength and high vibration damping is extremely important for ensuring high safety and reliability of composites in high-frequency-vibration circumstances. In this paper, we proposed a novel strategy to remarkably enhance the damping property of composites by introducing reversible hydrogen bonds at the interfaces of graphene/polymer composites. Graphene and poly(styrene-ethylene-butadiene-styrene) (SEBS) were chemically modified to graft hydrogen bonding moiety, consequently forming multiple hydrogen-bonding networks at interfaces of graphene/SEBS composites. The cyclic tensile behavior and dynamic mechanical properties of the composites were investigated in detail. The results showed that the mechanical and damping properties of graphene/SEBS composites were greatly improved by introducing graphene and interfacial hydrogen-bonding structures. The elastic modulus, hysteresis loss, and damping ratio of the graphene/SEBS composites were increased by 165%, 237% and 42% in comparison with that of SEBS. Such remarkable enhancement in both mechanical and damping properties is mainly attributed to the interfacial hydrogen bonds between components, high-efficiency stress-transferring, and significant energy dissipation resulted from reversible breaking/formation of hydrogen bonds during cyclic deformation.

The sliding tribological behavior of rare earth-modified GCr15 bearing steel against bakelite cage material was investigated via ring/block tester under grease lubrication conditions, in comparison with the ordinary GCr15 bearing steel. The results show that although the measured friction coefficient between rare earth GCr15 steel and bakelite material is larger, its wear volume is smaller than the ordinary GCr15 steel; both bearing steels have experienced material removal mainly caused by abrasive wear, and their wear volume tends to decrease with the increasing rotation speed; only furrows can be seen on the surface of the wear scar of rare earth GCr15 steel, while the ordinary GCr15 steel has more flaking in addition to the furrows that are removed during abrasive wear. The influence of the rare earth induced microstructural improvement of the GCr15 steel on its service behavior is discussed in terms of carbides, non-metallic inclusions and retained austenite. It follows that although rare earth modification reduces the hardness of bearing steel to a certain extent, but it can effectively suppress the fracture removal mechanism in abrasive wear, that GCr15 bearing steel inevitably appears during service, i.e., material spalling, thereby its wear resistance under sliding friction conditions is improved.

Creep tests of Nickel-based single crystal superalloy DD413 were carried out by constant loads of 980℃/200 MPa and 870℃/430 MPa, while which then were terminated at plastic strain just reaches 0.2%, 0.5% and 1% respectively, so that to acquire the microstructure of the alloy by different creep damage states. Later on, the pre-strained alloys were further subjected to re-creep test again, so as to acquire their residual creep properties and to establish the relationship between different degraded microstructure and creep properties. Meanwhile the microstructure damage characteristics of DD413 alloy under thermal-mechanical coupling were simulated and quantitatively characterized. The results show that the degradated damage of DD413 alloy structure mainly includes the decrease of γ' phase volume fraction and the increase of γ' phase rafting degree. The higher the creep temperature, the more serious the microstructure damage, and the worse the alloy's re-creep performance. Compared with γ' phase rafting, the decrease of γ' phase volume fraction has little effect on the creep properties of the alloy.

The effect of addition of Ta and Zr on the evolution of the second phase precipitation and microhardness of Fe-Cr-Al-Mo-Nb alloys was investigated. For this purpose, a series of alloy ingots were prepared by vacuum arc melting in high purity Ar gas and homogenized at 1473 K/2 h. After solid solution treatment, the four ingots were hot rolled to produce plates, which then were annealed at 1473 K for 10 min, and then warm rolled successively at 1073 K and 873 K to obtain metal sheets of 2 mm thick, followed by aging treatment at 873 K/24 h and heat treatment at different temperatures. After the final heat treatments, the alloy sheets were characterized by means of XRD, OM, SEM, and EPMA. while their mechanical property was examined by material testing machine. The results show that the aging alloys are mainly composed of two Laves phases with different sizes, and the addition of Zr promoted the precipitation of fine particles, while inhibited the precipitation of coarse particles. With the increase of the heat treatment temperature, the second phase particles are significantly coarsened and redissolved. After heat treatment at 1473 K/1 h, the Zr and Ta/Zr modified alloys exhibited high microstructural stability, but significantly inhibited the re-solvation of the second phase particles, thereby resulted in that the two alloys presented second phase with volume fraction of 0.1% and 0.2% respectively. The addition of Zr also significantly inhibited the coarsening of grains at high temperatures, correspondingly which was associated with the pinning of grain boundaries by Laves phase particles.

Graphite-based solid lubricating coatings were prepared on Ti-6Al-4V substrate by the slurry method with graphite as solid lubricant, silica as filler, sodium silicate as binder and deionized water as dispersion medium. The tribological properties of the coatings were evaluated by a ball-on-disk friction and wear tester at 500~800℃. The microstructure, chemical composition, elements state and phase constituents of the coatings were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS), respectively. The lubrication mechanism of the coating was also investigated. The results show that the coatings have excellent adhesion, anti-friction and anti-wear properties at 600~700℃. The coatings present the lowest friction coefficient (0.03) and wear rate (0.953×10^-4 mm³/(N·m)) at 660℃. At the same time, the co-lubrication of molten sodium silicate and SiO₂ in the coating reduces the heat loss of graphite, and the shear viscous component generated on the friction interface reduces the friction and wear. In the process of friction, graphite produces good lubrication performance through interlaminar shear and adsorption gas, SiO₂ enhances the bearing capacity of the coating and the bond strength between the coating and the matrix, so that the wear resistance of the coating was improved.

A new refractory medium-entropy alloy of CrTaTi has been successfully developed through the reasonably composition design, and the room-temperature mechanical properties and high-temperature oxidation resistance of the alloy were systematically investigated in this paper. The results show that the as-cast alloy is composed of bcc phase matrix and a small amount of Cr₂Ta Laves phase. The solid solution strengthening and precipitation strengthening make the alloy with good comprehensive mechanical properties at room-temperature. During the short-term oxidation test at medium- and high-temperatures a composite oxide scale containing TiO₂ and Cr₂O₃ preferentially formed on the alloy surface, showing excellent oxidation resistance. The oxidation weight gain of CrTaTi alloy is only 8.4 mg/cm² after oxidation in air at 1000℃ for 10 h.

α-Ni(OH)₂ materials with micro/nano hierarchical structure were prepared by a facile homogeneous precipitation method with sodium dodecyl sulfate (SDS) as accessory ingredient. It was found that the introduction of SDS can refine the grain size of α-Ni(OH)₂ and facilitate the formation of micro/nano hierarchical morphology with a more open structure as evidenced by XRD, SEM, FT-IR, TGA, and XPS analysis. Results of electrochemical test demonstrate that the α-Ni(OH)₂ sample synthesized with the n(SDS)/n(Ni²⁺) of 2∶10 exhibits the best lithium ions storage performance. After 40 cycles at the current density of 2 A·g^-1 the α-Ni(OH)₂ sample maintained a specific capacity of 800 mAh·g^-1; even at the high current density of 3 A·g^-1 it still delivered a reversible specific capacity of 710 mAh·g^-1. Moreover, it shows a significant pseudo-capacitive effect during discharge/charge processes (the pseudo-capacitive contribution to the total stored charge is as high as 84.2% at 0.9 mV·s^-1).

Rolling can accelerate the aging precipitation behavior, whilst shorten the incubation time for the emerge of peak aging. The Al-2Mg-0.8Cu alloy with 80% reduction reaches peak aging after annealing for 1 h. The maximum solid solubility of Si in Al-2Mg-0.8Cu alloy is 0.3% (mass fraction), which can further accelerate the kinetics process of aging precipitation and refine the size of S-phase. The Al-2Mg-0.8Cu-0.15Si alloy after cold rolling with 40% reduction achieved the properties of yield strength of 240 MPa, tensile strength of 353 MPa, elongation at break of 16.5% and tensile strength-plastic product of 5.66 GPa·%. 40% cold rolling reduction and addition of 0.15% Si (mass fraction) are the optimal process combination to obtain the best mechanical properties.

C/C-ZrC-SiC composites have high specific strength, high specific modulus and good resistance to high-temperature ablation. At the same time, ZrC, SiC and carbon matrix materials have low neutron absorption cross-sections, which are candidate materials for future nuclear energy systems. In order to assess the application possibility of C/C-ZrC-SiC composites in the field of nuclear energy, C/C-ZrC-SiC composites was irradiated with ion beam of 2 MeV Si²⁺ at room temperature. Then the effect of Si²⁺ ion beam irradiation on the performance of C/C-ZrC-SiC composites was examined by means of grazing incidence X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy and nanoindentation test, in terms of their crystallographic structure, lattice damage, microstructure, surface morphology and micromechanical properties etc. The results show that the irradiation of Si²⁺ion beam can induce stress within the SiC lattice, which then leads to an increase in the interplanar spacing of SiC, while the ZrC lattice does not expand; After irradiation, Raman peaks of SiC are broadened and shifted, correspondingly new peaks emerged in the Si-C region; The ion irradiation can induce carbon vacancies within ZrC, resulting in the formation of characteristic peaks; The surface morphology of ZrC, SiC and carbon fiber don't change significantly after irradiation, but the atomic ratio of carbon atom in ZrC and SiC increase by 13.03% and 23.21%, respectively; A large number of interstitial defect clusters appeared in ZrC, while SiC was partially amorphized, and a completely amorphized region appeared at the junction of ZrC and SiC grains; The I_D/I_G value and the interplanar spacing of graphite crystallites increase, and the layered structure of pyrolytic carbon is destroyed and gradually disordered; the nano-hardness and elastic modulus of ZrC, SiC and carbon fibers increase, with the best stability with the smallest degree of increase in nano-hardness and elastic modulus.