The interface chemical bond, potential fiber de-bonding fracture, potential fiber slip fracture and slip hardening interface characteristics were concerned based on the micron-scale pull-out characteristics of single staple fiber from the hardened matrix. The crack bridging stress-crack (σ_B-δ)opening relationship based on high ductility cementitious composite (HDCC) design theory was analyzed, and the (σ_B-δ)relation model of HDCC was proposed. In addition, the established model was verified by the experimental test data, indicating that the properties (i.e., tensile strength and average crack opening after failure) of HDCC predicted by the model are in reasonable agreement with the experimental results.

Chalcogenide glass possesses significant potentials for applications in photonic devices due to its high refractive index, wide infrared transparency window, low nonlinear loss, and fast nonlinear response. With the development of nanofabrication technology in recent years, novel micro/nano photonic devices based on chalcogenide glass have been widely used in the fields of telecommunication, security, medical and environmental applications. In this review, recent work on the preparation technologies of chalcogenide glass thin films, micro-/nano-device fabrication methods, the application and future prospects of chalcogenide glass optical devices was represented, respectively, based on the physical and optical properties of chalcogenide glasses.

This review represented some topics for molecular dynamics (MD) simulation, i.e., the initial conditions, algorithms, empirical potentials, and thermodynamic ensembles, and their application in simulation of glass materials. The methodologies of structural analysis and property calculation of glass materials were summarized. Recent development on the MD simulations of glasses, such as the structure model of oxyfluoride glass, the design of glass ceramics with target crystal phase, the prediction of compositional-dependent crystallization phase evolution and crystalline phase transformation via simulation of phase separation, optimization of the luminescent performance of glass ceramics, and improvement of the mechanical strength of aluminosilicates glass were represented. In addition, three future research directions were also prospected, i.e., the parameters of the simulation system to improve the accuracy of the results, the potential function with the help of first-principles molecular dynamics, and the practicability of the simulation with combining other methods.

According to MgO-A1₂O₃-SiO₂ ternary system phase diagram, 22 kinds of compositions were designed by using triangular rule, and cordierite was synthesized by melting sintering method. The crystal evolution and phase transition of cordierite glass-ceramics was studied by means of differential thermal analysis, X-ray diffraction and scanning electron microscope. The apparent porosity and thermal expansion properties were tested. The results show that there are two kinds of exothermic peaks in the differential thermal curve with the change of composition. Near the theoretical composition, a double crystallization exothermic peak occurs, and MgAl₂Si₃O₁₀ and α-cordierite crystal phase is precipitated. The thermal expansion coefficient of cordierite under the theoretical composition is the lowest, which is 1.27×10^-6/℃. However, when the MgO content in the composition increases to more than 16.6%, the exothermic peak of crystallization is unimodal, and only α-cordierite crystal phase is precipitated under the single peak. At this time, the apparent porosity of cordierite sample is on the decrease significantly, with a minimum value of 0.32%.

This paper summarized advanced one-dimensional and two-dimensional solid-state nuclear magnetic resonance techniques for the analysis of rare-earth element doped oxyfluoride glass and glass ceramics. This paper also represented the application of solid-state NMR technology in the analysis of the short-range coordination structure of rare-earth element ions, the distribution of rare-earth element ions in glass and crystal phases, the coordination structure of F ions, the agglomeration of F ions and the atomic scale structure of glass networks as well.

Joule heated ceramic melter (JHCM) in vitrifying high-level liquid waste (HLW) has attracted recent attention due to the unrestricted melter size, high glass production yield, and good compatibility with noble metals. The existing JHCM still prevails in the HLW vitrification. This paper reviewed recent research progress on the key technology of JHCM according to the engineering application of JHCM in US, Russia, Germany and Japan. In order to enhance the volume reduction ratio and reduce the cost, the future development of JHCM should focus on designing the melters with a high glass pool temperature, a high glass yield, and a good compatibility with noble metals based on the critical materials (i.e., refractory and alloy) and HLW compositions.

Three kinds of mullite-SiC materials were prepared with homogenized bauxite aggregate, porous mullite aggregate and glass ceramic coated porous mullite aggregate, respectively. The physical properties of the mullite-SiC materials sintered at 1 500℃ were investigated. The structure and properties of the materials after alkali vapor attack at 1 000℃ were analyzed. The influence of glass ceramic coating on the alkali vapor attack resistance of material was revealed by thermodynamics analysis. The results show that the strength of the lightweight mullite-SiC material is similar to that of the conventional mullite-SiC materials. However, the lightweight mullite-SiC material has a poor alkali vapor attack resistance. A liquid phase formed in glass ceramic coating at a high temperature promotes sintering, leading to a stronger bonding between aggregates and matrix and an increase in the strength for coated lightweight mullite-SiC materials. Moreover, the glass ceramic coating can absorb a part of K vapor and generate a liquid phase, thus protecting the porous aggregate from alkali vapor. The alkali vapor attack resistance of the lightweight mullite-SiC material is better than that of the conventional mullite-silicon carbide material.

In order to improve the thermal shock resistance of magnesia aggregates, MgO-ZrO₂ refractory aggregates were prepared at 1 600℃ via adding 5% (in mass fraction), 10%, 15% and 20% of m-ZrO₂ powder into light burned magnesia powder. The effect of ZrO₂ content on the sintering behavior, microstructure, mechanical properties, thermal properties and thermal shock resistance was investigated. The results show that ZrO₂ is mainly distributed at the grain boundary of periclase, which can inhibit the abnormal growth of periclase grains and promote the discharge of pores. Some m-ZrO₂ interacts with MgO to form c-ZrO₂ solid solution, thus activating the periclase lattice and promoting the sintering and densification of specimens. However, more than 10% ZrO₂ addition can lead to the more micron-cracks formation at the grain boundary of MgO, which can slightly reduce the density of the specimens. For a specimen with ZrO₂, the strength of the specimen reduces slightly and the main crack propagation mode becomes intergranular fracture due to the weakened intergranular bonding of periclase. Also, crack deflection and branching effect occurs after adding ZrO₂, leading to an improvement of the fracture toughness K_IC, and the specimen with 20% ZrO₂ addition has the optimum K_IC due to its smallest MgO grain and the longest crack propagation path. In addition, although the addition of ZrO₂ results in a decreasing thermal conductivity λ, the K_IC of the specimen increases and the coefficient of thermal expansion α decreases, the thermal shock resistance of the specimen improves. The specimen with 5% ZrO₂ addition has an optimum thermal shock resistance due to its maximum residual flexural strength and residual flexural strength retention rate.

The phase transformation, structure evolution and reaction mechanism of Al₄O₄C in high-temperature nitrogen were investigated. The experimental results indicate that Al₄O₄C reacts with nitrogen at > 7 00℃, and the nitridation reaction is composed of several cyclic processes, i.e., surface reaction, internal diffusion and mass transfer reaction. In the initial stage, nitridation reaction occurs on the surface to form a composite reaction layer of AlN, Al₂O₃, and C, which inhibits the diffusion of nitrogen. The nitridation reaction rate increases and the volume expansion effect associated with the formation of a large amount of AlN causes Al₄O₄C reaction layer to crack when the temperature increases. The loose and porous surface structure from the staggered growth of Al₂O₃ and AlN as gas diffusion channels can accelerate nitrogen diffusion and reaction. When the nitridation temperature is 1 600℃, the intermediate products of Al₂O₃, C, and N₂ undergo a carbon-thermal reduction and nitridation reaction, accompanied with massive gas phase generation. The more sufficient the AlN particles develop, the more complete the crystal grain morphology will be.

A strontium zirconate oxide refractory was prepared by a solid-state reaction method at a mole ratio n(SrO): n(ZrO₂) of 2∶1 and 1 400℃, and Ti₂Ni alloys were melted in a crucible at 1 750℃. The phase composition and microstructure of the refractory as well as the key features of Ti₂Ni alloy melt interacted with the refractory crucible were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscopy (OM). The results reveal that the crucible refractory is consisted with the phases of Sr₂ZrO₄, Sr₃Zr₂O₇ and SrO, respectively. The thermodynamically stable phase Sr₂ZrO₄ is unable to obtain separately due to the limitation of the reaction between SrCO₃ and ZrO₂, causing the residues of Sr₃Zr₂O₇ and SrO. The thickness of interaction layer for the strontium zirconate oxide and barium zirconate crucible are 1 250 μm and 2 120 μm, respectively. The oxygen concentrations of the alloy after melting in strontium zirconate oxide and barium zirconate crucible are 0.332% and 0.566% (in mass fraction), respectively. It is indicated that the strontium zirconate oxide refractory exhibits a superior stability, compared to the barium zirconate refractory.