The typical superalloy GH4169 was prepared by selective laser melting (SLM), and then subjected to appropriate post-heat treatments, afterwardsits tensile properties was assessed in temperature range 25~650 ^oC. The microstructure evolution, tensile behavior at different temperatures were examinedby scanning electron microscopy and transmission electron microscopy, and the corresponding deformation mechanism of SLM GH4169 alloy was disscussed. The results show that the tensile curves of the of SLM GH4169 alloy are monotonic and smooth at 25 ^oC, 600 ^oC and 650 ^oC, but those at 450~550 ^oC are sawtooth-like. With the increasing test temperature, the tensile strength and yield strength of the SLM GH4169 alloy decreases from 1458 MPa to 1228 MPa and 1234 MPa to 1051 MPa respectively. The relationship between tensile strength and temperature of the SLM GH4169 is roughly linear with an error is less than 2%.The strengthening phases may obstruct the dislocation movement and plays a certain strengthening role in the temperature range 25~450 ^oC. While in the range 550~650 ^oC, slip bands may be the main deformation mode, and δ phases also has an adverse effect on tensile properties.

A high-performance carboxyl-terminated liquid fuoroelastomers (SCTLF) was synthesized by a one-pot oxidative degradation/fluorination addition synergistic reaction for the first time, with 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2,2,2]octane bis(tetrafluoroborate)(Selectflour) as fluorination reagent, tetrabutylammonium fluoride (TBAF) as nucleophilic reagent, and N-bromosuccinimide (NBS) as electrophilic reagent. This reaction system can simultaneously eliminate the fluorinated double bonds (C=C), increase the fluorine content, enhance their thermal stability, and thereby achieve high performance of the products. The molecular chain structure of the synthesized SCTLF was characterized by using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H-NMR), and fluorine nuclear magnetic resonance (¹⁹F-NMR). Besides, its molecular weight and terminal group content was determined by means of gel permeation chromatography (GPC) and chemical titration method. After the fluorination addition reaction, SCTLF had average molecular weight of 2410, carboxyl content of 2.30%, and C=C content decreased from 0.30 mmol/g to 0.08 mmol/g. The fluorinated C=C conforming to Zaitsev's rule showed high reactivity and complete reaction, while those conforming to Hofmann's rule had some residuals, with a calculated fluorine content of 65.47%. The glass transition temperature (T_g) of SCTLF was -34 ^oC, and its initial thermal decomposition temperature (T_d) significantly increased to 270 ^oC. At 20 ^oC, its dynamic viscosity was 46 Pa·s. The curing of SCTLF with HDI trimer resulted in a cured product with excellent mechanical properties and chemical stability.

A series of medium manganese test steels of non-carbide bainite structure were prepared by isothermal quenching heat treatment. The evolution of the inner- and outer-portion of corrosion products on the steels (1200 MPa class) and the effect of the microstructure of corrosion products on its corrosion resistance were studied via periodic immersion accelerated corrosion test in 3.5% NaCl solution and electrochemical corrosion measurement so that to simulate the corrosion situation encountered in the ocean splash zone. The results show that after being heated to 920 ^oC for 30 min and then quenched quickly in salt bath of 340 ^oC for 2 h, the steel presents an uniform and fine microstructure with clear lath boundaries, while its yield strength, tensile strength and elongation at breaking are 1297 MPa, 1402 MPa, and 29.3%, respectively. With the increase of corrosion time, the inner portion of corrosion products gradually changed from the loose porous γ-FeOOH in the initial stage to the dense α-FeOOH in the later stage of corrosion. The alloying elements beneficial for enhancing corrosion resistant such as Cr and Cu were enriched in the inner portion of the corrosion products, and stable compounds such as FeCr₂O₄ and CuFe₂O₄ were formed. With the increase of pre-corrosion treatment time, the corrosion current density first increases and then decreases, the corrosion potential first shifts negatively and then positively, the charge transfer resistance increases, and the protective effect of the corrosion product film is gradually enhanced. With the increase of the enrichment degree of corrosion resistant elements in the inner portion of corrosion products, the corrosion current density decreases, the charge transfer resistance increases, and the corrosion resistance increases.

To address the current issues of low interfacial bonding strength and complex process flow in titanium-steel composite pipes, herein, composite pipes of TA2 Ti-alloy/Q345 steel were fabricated via hot-assembling and diffusion welding technique. The microstructure and mechanical properties of the interface of TA2/Q345 composite pipes made by different processing conditions were investigated. The results show that the bonding strength of the TA2/Q345 composite pipes is 62.32 MPa after hot assembled at 550 °C. After subsequent diffusion welding at 850 °C for 2 hours or at 950 °C for 30 minutes, the bonding strengths rise up to 167.44 MPa and 256.53 MPa, respectively. Transition layers in between TA2 and Q345 ranging from 1.2 μm to 40 μm were observed under all the three making conditions, which mainly composed of TiC, FeTi, and Fe₂Ti. The formation of these phases promoted atomic bonding of the interface, enhancing bonding strength. The fracture mode of the shear fracture surface of the hot assembled composite pipe was ductile fracture with numerous transgranular dimples, while the fracture mode of the shear fracture surface of the diffusion welded composite pipe was quasi-cleavage brittle fracture. No significant defects were detected on the composite interface after infrared nondestructive test.

In order to enhance the tribological properties of Al-alloy moving parts, a Ni-Ti₃AlC₂ composite coating was applied onto the surface of ADC12 Al-alloy using high-pressure cold spraying technology. During the cold spraying process, spraying pressure and temperature are identified as two critical process parameters. In this study, while keeping the spraying pressure constant, the impact of spraying temperature on the microstructure, mechanical properties, and tribological behavior of the Ni-Ti₃AlC₂ composite coating/ADC12 Al-alloy was assessed. The findings indicate that with an increase in spraying temperature from 500 ^oC to 700 ^oC, there is a rise in plastic deformation degree of particles within the Ni-Ti₃AlC₂ composite coating leading to significantly improved bonding state between particles. This results in a 30% increase in coating bonding strength, a 60% decrease in porosity, a 14% increase in hardness, and a 41.7% reduction in coating wear rate. It is evident that appropriately elevating the spraying temperature may effectively enhance the density, mechanical properties and wear resistance of the coating. For spraying at 700 ^oC specifically, Ni-Ti₃AlC₂-700 ^oC exhibits the densest microstructure with no discernible pores or cracks which signifies superior mechanical properties as well as friction and wear characteristics. This can be attributed to the higher spraying temperature enhanced the striking velocity of composite particles, thereby improving deformability of Ni particles, thus the adhesion between Ni particles and Ti₃AlC₂ ceramic particles, as well as the adhesion between the coating and substrate may be significant enhanced. As a subsequence, the mechanical properties and frictional behavior of the coating can be substantially improved.

The Mn_{1 - x} Zn _x Fe₂O₄ (x = 0.1, 0.3, 0.5, 0.7, 0.9) powder materials were prepared by the “chemical sol-spray drying-calcination” method. The prepared powders were characterized by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photon-electron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscopy (TEM), and superconducting quantum interference magnetic measurement system, in terms of phase composition, microstructure and magnetic properties etc. The results indicated that when the Zn concentration was x = 0.5 or above, MnZn ferrite powders of single-phase can be obtained. When the Zn concentration was below x = 0.5, impurity α-Fe₂O₃-phase will appear. The lattice constant of MnZn ferrite phase showed a trend of first decreasing, then increasing, and finally decreasing again with the increasing Zn concentration. As the Zn concentration increased, the FTIR absorption peaks of MnZn ferrite phase showed monotonically red shift. The intensity of Raman peaks increased with the increase of Zn concentration. The valences of Fe and Zn were +3 and +2, while Mn exhibits different valence states, with +2, +3, and +4 valences. The prepared powders all presented hollow spherical shell morphology, with no abnormally large particles observed. With the increase of Zn concentration, the variation range of the saturation magnetization (M_s) 8.99~55.87 emu/g, the remanence (M_r) 0.24~6.50 emu/g, the coercivity (H_c) 28.03~107.63 Oe, and the squareness ratio (M_r/M_s) 0.02~0.12, while the saturation magnetization (M_s) decreased monotonically (except for x = 0.5). Furthermore, when the Zn concentration was x = 0.5, the comprehensive characteristics of MnZn ferrite are optimal.

The application of anodic bonding, as an important technology in the semiconductor industry, in the field of flexible electronics encapsulation will be beneficial to the further popularization of the commercialization of flexible devices. The key solution is the preparation of high-performance polymer flexible substrates suitable for anodic bonding. Herein, three kinds of polyurethane-based composite elastomer cathodic materials (CPUEEs) for anodic bonding are prepared by room temperature casting, of which the microphase separation morphology can be observed by SEM. Results show that the CPUEEs present T_{d, 5%} above 200 ^oC with thermal stability meets the requirements of anodic bonding, besides, the CPUEEs present amorphous structure with T_g lower than -45 ^oC, and their molecular segments have good low temperature flexibility, which can provide the necessary space for lithium ion migration during anodic bonding. The ionic conductivity of all samples at the bonding temperature meets the bonding requirements, and the ionic conductivity value of CPUEE3 modified by blending with PPC and SN is the highest up to 6.5 × 10^-4 S·cm^-1. The anodic bonding of CPUEEs and aluminum foil (Al) may be realized by heat-guided dynamic field anodic bonding technique. The bonding interface of CPUEEs-Al can be clearly observed in the SEM image, and the bonding strength of CPUEE3-Al can reach up to 1.15 MPa.

The development of a low-cost and highly efficient electrocatalyst for replacing the noble metal-based materials and enhancing the efficiency of electrocatalytic generation of hydrogen is still a challenge. In this work, an amorphous FeOOH decorated CoFeAl LDH catalyst with hierarchically interconnected porous heterostructure was synthesized by a two-step method. Then, the performance of overall water splitting in alkaline solution of the prepared electrocatalyst was assessed.. Results show that by an applied current density of 100 mA·cm^-2 for the catalyst CoFeAl-FeOOH-6, the generation of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in 1 mol/L KOH solution requires only relatively low overpotentials of 298 and 193 mV, respectively. And their corresponding Tafel slopes are relatively small (i.e. 50.0 and 95.6 mV·dec^-1 for OER and HER respectively). Furthermore, the catalyst CoFeAl-FeOOH-6 as both anode and cathode in a two-electrode water splitting device can achieve excellent stability by a current density of 10 mA·cm^-2 at a cell voltage of 1.60 V. The systematical electrochemical measurement and characterization demonstrated that the enhanced electrocatalytic property of FeOOH decorated CoFeAl LDH electrode could be ascribed to the hierarchical interconnected nanosheet structure, the porous heterostructure, and the synergistic effect between them. This work could provide a promising route for promoting the electrocatalytic performance of LDH-based catalyst with a simple amorphization method, which may be expanded to other LDH materials for enhancing their electrocatalytic activities.