The effect of annealing-temperature on the microstructure and properties of the low-melting point high-entropy alloy Fe₃₅Ni₃₀Cr₂₀Al₁₀Nb₅ (molar ratio) were systematically investigated. The results show that with the increasing annealing-temperature, the volume fraction of Fe-Cr-rich fcc phase gradually decreases, while the volume fraction of Laves phase and B2-NiAl phase gradually increases for the as-cast alloy. The quasi-static compression test results show that the as-cast alloy has good compressive plastic deformation ability, and the yield strength of the alloy increases and then decreases as the annealing-temperature increases. The decrease in compression yield strength with the rising annealing-temperature is mainly attributed to the decomposition of the fcc phase at higher temperatures. The electrochemical test results show that the corrosion resistance of the alloy increases monotonically with the annealing-temperature, and the free-corrosion potential of the alloy annealed at 900^oC is -72.02 mV.

The effect of solution temperature and the relevant microstructure evolution on the creep behavior of a Re/Ru-containing nickel-based single crystal alloy was assessed, aiming to reveal the effect of the addition of high metlting point elements on the performance of the alloy. The results show that the residual eutectic is still persisted in the inter-dendritic region of the alloy after solution treated at 1328^oC; after the residual eutectic was eliminated by solution treated at 1332^oC, the creep lifetime of alloy may be enhanced from 321 h to 476 h at 1100^oC/140 MPa. The γ′ phase in the alloy was changed into rafted structure in the primary period of creep. In the late creep period, although the formed dislocation locks in γ′ rafts may impede the dislocations movement to enhance the creep resistance of the alloy, the alternated gliding of dislocations causes the tortuosity of γ/γ′ rafts to form sub-grains, which in turn may reduce the strength and creep resistance of the alloy. Especially, the reversed microstructure evolution of the rafted γ′ phase transformed into the block-like configuration may accelerate the strain rate of the alloy until fracture, which is thought to be the deformed and damaged features of the alloy in the later creep period. While the cause of the creep lifetime at 1140^oC being decreased to a great extent is attributed to the γ′ phase dissolved to diminish its size and volume fraction.

The free corrosion behavior and electrochemical properties of Al-Zn-In-Mg-Ga-Mn alloys, as anodes working with 2 mol/L NaCl and 4 mol/L KOH electrolytes were studied. Results revealed that in the two electrolytes, the corrosion potential (E_corr) of alloy anodes shifted negatively by 0.041 V and 0.018 V, and the free corrosion rates decreased by 0.2146 and 15.1 mg·cm^-2·h^-1, respectively in the contrast to those of pure Al anode. The electrochemical activity of pure Al anode was improved, while its free corrosion behavior was inhibited. In the 2 mol/L NaCl electrolyte, the discharge capacity peak of the alloy anode reached 2608.96 Ah·kg^-1, which was 55.59% higher than that of the pure Al anode. The highest energy density attained 1742.61 Wh·kg^-1, being 274.58% superior to that of the pure Al anode. The anode efficiency was 87.55%. In the 4 mol/L KOH electrolyte, the highest discharge capacity of the Al-Zn-In-Mg-Ga-Mn alloy anode was 1605.15 Ah·kg^-1, which was 131.27% higher than that of the pure Al anode. The highest energy density was 1404.83 Wh·kg^-1, which was 231.52% higher than that of the pure Al anode. The anode efficiency was 53.86%.

Zwitterionic hydrogel is one of the most promising cartilage repair and replacement materials with good biocompatibility and anti-bacteria adhesion properties. However, there is a certain gap involving in mechanical properties compared to natural cartilage, which greatly limits its practical application. Herein, the nano-hydroxyapatite was modified with dopamine by acid, and alkali conditions respectively to obtain a nanoparticle-modified composite hydrogel. It is found that an oxide film could form on the surface of nano hydroxyapatite modified by dopamine, and the benzene ring in the modified nano particles is combined to form a covalent bond with the zwitterionic hydrogel polymer chain. Meanwhile, dopamine improves the dispersity of nano-hydroxyapatite by acidic condition, thereby enhancing the thermal stability of zwitterionic hydrogel (decomposing until 323^oC), as well as its network structure strength (energy storage modulus of 2.7 MPa) and internal friction capacity (loss factor of 0.041). Moreover, the compressive strength of acid nanocomposite hydrogel arrives at 11.66 MPa, which is 32 times higher than that of pure PSBMA zwitterionic hydrogel. Thus, the structural characteristics and mechanical properties of acid nanocomposite hydrogels are similar to those of natural cartilage, which provides a significant reference for the design and preparation of bionic materials.

Based on Thermo-Calc calculation, a nanostructured bainite steel, which is suitable for making steel wire, with composition of Fe-0.8C-2Mn-1.5Si-1.5Cr-0.25Mo-0.25Ni-1Al-0.25Co-0.1V was designed. The influence of austempering treatment on microstructure and mechanical properties of the steel was investigated by means of scanning electron microscope (SEM), X-ray diffractometer (XRD), transmission electron microscope (TEM), thermal dilatometer, and tensile tester in terms of microstructures, thermal and mechanical properties etc. Results show that after austempering at lower temperature, the microstructure of the nanostructured bainitic steel is composed of nanostructured bainite ferrite lath, retained austenite and a little proportion of martensite. With the increase of austempering temperature, the transformation rate and the volume fraction of bainite ferrite increase. As the austempering time increases, the volume fraction of bainite ferrite increases, while the amount of undercooled austenite decreases, and the size and volume fraction of the massive M/A islands obtained at room temperature decrease. Due to the carbon partitioning sufficiently between the bainite ferrite and austenite, the stability of undercooled austenite is improved, and the proportion of brittle martensite in M/A islands is reduced significantly. This induces the transition of tensile fracture from mixed fracture to quasi-cleavage fracture. After being heated at 230^oC for 48 hours, the tensile strength and yield strength of the experimental steel were 1625 and 1505 MPa, respectively, with an elongation of 34.5%, indicating the best match for strength and toughness.

The compound Ca₂GdSbO₆ with a stable double perovskite structure is one of the high-quality materials used as a phosphor matrix. A new series of reddish-orange phosphors Ca₂Gd_{1 - x} SbO₆:xSm³⁺ (x = 0、0.01、0.02、0.03、0.04、0.05、0.06)were synthesized by high-temperature solid-state method. The phase composition, optical properties, crystal structure and chemical purity of the prepared phosphors were characterized via X-ray diffractometer (XRD), scanning electron microscope (SEM), photoluminescence spectroscope (PL), high-temperature fluorescence spectroscope and fluorescence decay lifetime measurement. The incorporation of Sm may endow the synthesized phosphor Ca₂Gd_{1 - x} SbO₆:xSm³⁺ with ions Sm³⁺ as its luminescent centers with the peculiar ⁴G_5/2→⁶H_7/2 transition of Sm³⁺ at 597 nm, so that the synthesized phosphor may emit the orange-red light at 597 nm under the excitation of the light at 407 nm. As the concentration of Sm³⁺ ions increase, the luminous intensity of Ca₂GdSbO₆:Sm³⁺ phosphors increases first, and then decreases. According to Dexter's theory, the concentration quenching is dominated by the electric dipole-dipole interaction, and the optimum doping of Sm³⁺ ions is concentration x = 0.03. The test shows that the color purity of the best-doped sample is about 99.3%, and the color coordinates are (0.6146, 0.3826). The thermal stability was further studied, and it was found that the emission intensity was only attenuated by 5.56% at 453 K. The above results show that the new red-orange light-emitting Ca₂GdSbO₆:Sm³⁺ phosphor is promising to be applied in the field of white LED.

Multiphase composite coatings CrN:a-C were deposited by multi-arc ion plating technology with Cr target, gases N₂ and C₂H₂ as source of Cr, N and C, respectively. The carbon content of the coating can be regulated by adjusting the C₂H₂ flow rate. The effect of carbon content on the composition, structure, mechanical properties, and tribological properties of CrN:a-C multiphase composite coatings was assessed by means of X-ray diffractometer (XRD), Raman spectroscope, field emission scanning electron microscope (FE-SEM), and multifunctional friction -wear tester. The results indicated that with the increase of carbon content, the structural characteristics of amorphous carbon of the coating were gradually obvious, while the compactness of the coating was decreased, which leads to the gradual decrease of the mechanical properties, but it still shows a higher hardness and adhesive strength to the substrate. CrN:a-C multiphase composite coatings exhibited better characteristics of low coefficient of friction and low wear rate during dry friction and friction in the presence of lubricating oil 5W-30, which are affected by carbon content and friction products. The coefficient of friction (CoF) and wear rate increase first and then decrease in conditions of dry friction and friction with lubricating oil respectively. Among others, the coating prepared by the C₂H₂ flow rate of 120 sccm presented CoF of 0.33 and 0.12, and wear rate of 1.3 × 10^-5 mm³/(N·m) and 7.4 × 10^-6 mm³/(N·m) in conditions of dry friction and friction with lubricating oil respectively, which was expected to provide effective anti-friction and anti-wear protection for friction pair.

CO₂-enchanced oil recovery technology has been widely used to enhance the profitability of oil fields. The leakage of CO₂ into the annulus environment results in the formation of strong corrosive annulus fluid there, which is ineluctable. Due to the fluctuations of annulus environmental parameters in the practice, therefore, to simulate the annulus environment in the laboratory may be very difficult. Based on the parameters of the real annulus environment, the impact of total pressure, partial pressure of CO₂ (P_{\mathrm{C}{\mathrm{O}}_{\mathrm{2}}}), pH value and temperature (T) etc., on the corrosion behavior of J55 steel are investigated by means of numerical simulation in terms of the parameters, electrochemical test and correlation analysis. Results shows that the P_{\mathrm{C}{\mathrm{O}}_{\mathrm{2}}} and T are the critical factors influencing corrosion behavior. The Spearman correlation coefficient (r) between P_{\mathrm{C}{\mathrm{O}}_{\mathrm{2}}} and charge transfer resistance (R_ct) is -0.623, where the significant level is 0.013 (2-tailed), which means that the R_ct is significantly correlated with the P_{\mathrm{C}{\mathrm{O}}_{\mathrm{2}}}. The increasing P_{\mathrm{C}{\mathrm{O}}_{\mathrm{2}}} can decrease the pH value of the simulated annulus environment and accelerate the corrosion of J55 steel. The r between T and R_ct is -0.692, where the significant level is 0.004 (2-tailed), which means that the R_ct is significantly correlated with the T. The decreasing temperature can reduce the reaction activity of J55 steel, mitigate the corrosion and restrict the formation of FeCO₃ scale. The initial pH of the simulated solution has a little promoting effect on the corrosion of J55 steel, which may be covered by the effect of T and P_{\mathrm{C}{\mathrm{O}}_{\mathrm{2}}}.