The effect of heat treatments including quenching and tempering on the microstructure and mechanical properties of Cu-bearing high strength low alloy steel after being hot rolled at different temperatures were studied by SEM, TEM, STEM-HAADF and SASX. The results show that after being hot rolled at different temperatures, the test steels presented a microstructure of ferrite + bainite, however, which after quenching and tempering transformed to tempered martensite and a large amount of dispersed nano precipitates as their primary microstructure characteristics. The nano precipitates mainly consist of Cu-rich particles and Cr carbides. The results of TEM observation show that two types of precipitation modes, i.e. 9R precipitates with or without twins, can be found for the precipitation of Cu-rich particles in the test steel. The ambient temperature yield strength and low temperature impact toughness (especially at -84 ^oC) of the test steel can be significantly improved by quenching and tempering treatment, while the ultimate tensile strength is slightly decreased. The improvement in comprehensive mechanical properties of the test steel may be mainly ascribed to the precipitation of Cu-rich particles.

Herein, composites PGS@Zn-In LDO/ZnS/In₂S₃ were prepared by hydrothermal method with palygorskite (PGS) supported Zn-In LDO (PGS@Zn-In LDO) and thioacetamide as raw materials, namely in situ growth of ZnS and In₂S₃ on PGS@Zn-In LDO. The light absorption region of PGS@Zn-In LDO/ZnS/In₂S₃ composites is wider than that of the plain PGS@Zn-In LDO in ultraviolet-visible diffuse reflection spectrum. Photoluminescence spectrum and electrochemical impedance spectroscopy test results show that palygorskite is beneficial for the movement of photogenic charge carrier in Zn-In LDO/ZnS/In₂S₃ composites. After being subjected to a simulate visible light irradiation for 60 min, the 50% PGS@Zn-In LDO/ZnS/In₂S₃-2 composite as photocatalyst can even show a degradation rate up to 99.1% for methyl orange, exhibiting the composite possess better catalytic stability. In contrast, the common cations and anions in solution hardly effect on the photodegradation reaction except H₂PO₄^-. It is proposed that the superoxide radicals and vacancies may played a key role in the photocatalytic degradation reaction of MO. Therefore, it may be expected that the degradation rate of acid fuchsin, crystal violet, rhodamine B, malachite green and methylene blue and other common dyes is not less than 97.2% in the same testing conditions.

The recovery of phosphorus (P) resources from wastewater can alleviate the problem of eutrophication and shortage of phosphate resources. Herein, a flower-like hybrid film of Co-Ni layered double hydroxide grown on graphene doped polypyrrole (PPy-G/CoNi-LDH) with exclusive separation property for phosphate ions was successfully fabricated by using two-steps electrodeposition method, which may be applied for separation and recovery of low concentrated phosphate anions via electrically switched ion exchange (ESIX). The composition, morphology and structure of PPy-G/CoNi-LDH hybrid film were demonstrated by XRD, SEM, XPS, and TEM. The effect of various influencing factors, including phosphate concentrations, absorption potentials, acid-alkalinity, co-existing anions and their concentrations on the electrochemical adsorption performance of hybrid film was also investigated. The results indicate that the increase in absorption potentials and initial concentrations of wastwaters could enhance the adsorption capacity. The adsorption capacity of PPy-G/CoNi-LDH hybrid film for PO₄^3- in 10 mg·L^-1 PO₄^3- solution was 40.23 mg·g^-1 by an applied absorption potential of 0.8 V. In addition, in conditions of neutral and slightly alkaline solutions, PPy-G/CoNi-LDH hybrid film had good adsorption capacity, and it was minimally affected by coexisting ions and their concentrations. After 7 cycles of adsorption/desorption, the adsorption capacity PPy-G/CoNi-LDH hybrid film still maintained good stability.

The microstructure, micro zone properties, fracture morphology, and mechanical properties of different areas for the resistance spot welding joint of SUS301L stainless steel are systematically characterized via microhardness tester, electronic tensile shear testing machine, SEM, and IBIS. The results indicate that the morphology of the fusion zone in the joint is elliptical and which can be differentiated into the base metal zone, heat affected zone, and nugget zone. The microstructure distribution from the edge of the fusion core to the core center is columnar structure and equiaxed structure in sequence. The main defects of the joint include sputters on the edge of the fusion core, shrinkage porosity in the fusion core, and micro cracks, and the sputtering phenomenon is closely related to the occurrence of shrinkage porosity. The size of the nugget diameter is a key indicator that affects the mechanical properties, and there is a positive correlation between the two. As the thickness of the double-layer plate increases, the maximum tensile and shear force increment caused by the increment of the unit nugget diameter also significantly increases. The hardness and strength of the heat affected zone are lower than those of the base metal zone and the fusion zone, which leads to the formation of a softening zone at the corona bond. Due to the lower strength of this zone, the tensile shear force it can bear is relatively small, making it the starting area for tensile shear cracking. The forms of tensile shear fracture may be differentiated into passing through-core fracture and along-core fracture, the nugget diameter will affect the fracture mode of the joint.

The microstructure, tensile properties, low-cycle fatigue properties and corresponding damage mechanisms of typical compacted graphite cast irons RuT300 and RuT450 for engine cylinder head and block were studied at room temperature. The differences in properties and damage mechanisms between the two materials were systematically compared. The results show that the tensile strength and low-cycle fatigue life of RuT450 are higher than those of RuT300, but the difference of low-cycle fatigue life is small, which is mainly due to the difference in pearlite and ferrite content. The high content of lamellar pearlite in RuT450 leads to more serious tension-compression cyclic stress asymmetry. Fatigue cracks preferentially propagate between clusters composed of graphite and ferrite, and the increase of pearlite content has a certain effect on improving the tensile strength and low cycle fatigue life of compacted graphite cast irons. The Basquin & Coffin-Manson model can effectively predict the low-cycle fatigue life of compacted graphite cast irons.

Lithium disilicate glass-ceramics of Li₂O-K₂O-MgO-Al₂O₃-SiO₂-ZrO₂-CeO₂-P₂O₅ were prepared by melting-crystallization method. The effect of Er₂O₃ addition on the crystallization, microstructure and properties of the glass-ceramics was investigated. The results show that Er₂O₃ has significant regulating effect on the precipitation, microstructure and properties of the glass ceramics. When an appropriate amount of Er₂O₃ (0.4%, mole fraction) was added to the glass, it could effectively reduce the crystallization activation energy of Li₂SiO₃ and Li₂Si₂O₅, and promote glass crystallization. The prepared glass-ceramics have interlocked grains, while the glass phase is closely bound to the crystal phase, which helps to prevent crack extension and achieve the best mechanical properties. The average three-point flexural strength reaches (376±61) MPa, with the microhardness reaching (6423±284) MPa, and the glass ceramic exhibits good translucence. Whereas, when an excessive amount of Er₂O₃ is added to the glass, the increase in the size of the precipitated crystals and the enhancement of the coloring effect of Er³⁺ will lead to a decrease in the mechanical properties and transparency of lithium disilicate glass ceramics. This work is of great significance for developing lithium disilicate glass ceramics and promoting their application in dental prosthetics.

Fe₃O₄@NaX magnetic zeolite was prepared via alkaline fusion hydrothermal method with Fe₃O₄ particles and Beipiao oil shale ash as raw material, aiming to making magnetic absorbent substance for absorbing methylene blue (MB) from waste water. The adsorption performance of the magnetic zeolite for MB were studied in various processing conditions, and the adsorption mechanism was revealed. The results show that the removal efficiency and equilibrium adsorption capacity of 2.0% Fe₃O₄@NaX (mass fraction) zeolite for MB were 96.98% and 45.19 mg/g, respectively, in the following adsorption conditions: zeolite dosage of 1 g/L, initial pH of 5.7 of the solution, initial MB concentration of 50 mg/L, adsorption temperature of 25 °C and adsorption time of 60 min. The magnetic zeolite can be separated rapidly from dye solution by an applied external magnetic field, indicating its excellent recyclability. The MB adsorption on the zeolite is a spontaneous and exothermic process of entropy reduction, which follows the pseudo-second-order kinetics and Langmuir isotherm models. The electrostatic attraction, hydrogen bonds and pore diffusion are the main driving forces of the adsorption process.

YBCO superconducting solders were prepared on YGdBCO superconducting layers of tapes by fluorine-free chemical solution method. The effect of high temperature heat treatment on the structure of solders and superconducting properties of tape was investigated. The results show that the YBCO polycrystalline film with strong (103) diffraction peak and uniform grain distribution was obtained by sintering the amorphous precursor film at 795 ^oC for 1 h. Then the polycrystalline film was transformed into YBCO single crystal film (solder) with (00l) orientation after sintering it at 820 ^oC for 30 min. After annealing in oxygen, the critical current I_c of the tape deposited with YBCO single crystal film is close to that of the original tape, indicating no obvious influence of the growth of superconducting solder on the superconductivity of the tape.