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To understand electrochemical properties of the rare earth-doped CaZrO3 system in more detail, a solid-state electrolyte Er-doped CaZrO3 was successfully prepared using solid-state reaction method at the temperatures of 1673 K and 1823 K for 10 h. The microstructures and electrochemical properties of these materials were systemically investigated. The results from structural analysis showed that the electrolyte has a pure perovskite phase structure. According to the H/D isotope effect, protons were determined as the dominant charge carriers in hydrogen atmosphere between 773 and 1273 K. The electrochemical impedance spectroscopy test showed that ionic electrical conductivities are approximately 1.86 × 10−8 ~ 2.93 × 10−4 S/cm at 773 ~ 1273 K, and ionic conductance activation energy (Ea) is in the range of 0.823–1.416 eV, Furthermore, ionic electrical conductivity decreases with increasing Er2O3 doping amount, which is completely different from that of In2O3 or other dopant-doped CaZrO3. The abnormal phenomenon is associated with the defect association introduced by incorporation of Er2O3 into CaZrO3 lattice on the basis of the DFT calculation.

In this work, Nb5+ and Cu2+ were selected to partially substitute Zr4+ in Gd2Zr2O7 for studying the phase structure, microscopic morphology and thermal properties. Gd2(Zr1-3x/2NbxCux/2)2O7 (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25) ceramic materials were synthesized by high-temperature solid-state reaction method. The results show that the Gd2(Zr1-3x/2NbxCux/2)2O7 ceramics present cubic pyrochlore structure with clear grain boundaries and dense cell structure. And the thermal expansion coefficient of Gd2(Zr1-3x/2NbxCux/2)2O7 ceramics gradually decreases because of the incorporation of Nb5+ and Cu2+ into Zr-site in Gd2Zr2O7. Meanwhile, its thermal conductivity decreases firstly and then increases with the doping of Nb5+ and Cu2+, which reaches the lowest value for the composition of Gd2(Zr0.85Nb0.1Cu0.05)2O7.

The low-temperature degradation and mechanical properties of 3Y-TZP-xYF3 ceramics synthesized by a conventional solid-state reaction were investigated. The addition of YF3 has a significant effect on the aging and mechanical properties of 3Y-TZP ceramics. The results show that the mechanical properties and aging resistance of 3Y-TZP-xYF3 ceramics with slow grain growth are greatly improved when the content of YF3 is maintained in a reasonable biphasic region (RBR) due to the dominant role of T-M (tetragonal to monoclinic). When the content of YF3 exceeds 0.15 mol%, the mechanical properties and aging properties of ceramics in a saturated biphasic region (SBR) decrease due to the influence of T-C (tetragonal to cubic). More importantly, 3Y-TZP-0.15YF3 ceramics have good aging resistance and mechanical properties, and YF3 doping makes the application of 3Y-TZP in dental ceramics more meaningful.

The aim of this investigation was to discuss the mechanical properties and aging-resistance of 3Y-TZP (3 mol% yttria-tetragonal zirconia with 0–0.25 wt% alumina added 3Y-TZP) by comparing the effect of high-energy ball milling zirconia powders (HP) and commercially available zirconia powders (CP). The results showed that a hardness of 12.93 GPa, combined with an excellent high-fracture toughness of 9.17 MPa m1/2, could be attained for HP-doped (0–0.25 wt% (Al2O3)) ceramics, as well as an increase in hydrothermal stability with the increase in Al2O3 content. The HP + 0.15 wt% (Al2O3) ceramics exhibited better antiaging performance and mechanical properties. These 3Y-TZP ceramics, with high-fracture toughness and better aging-resistance, which were prepared by a high-energy ball milling method, could meet the different demands of practical dental ceramics.

Tension-Tension fatigue tests of carbon fiber/epoxy composite blades were studied in this paper. The S-N curve was plotted to predict the fatigue life. Fracture surfaces were observed by SEM to analyze the failure mode under the variable spectrum. The results show that the conditional fatigue limit of the carbon fiber/epoxy composite blade is 302MPa. The major failure modes of the bolted joints include the first resin matrix microcracking, fiber-matrix splitting, delamination and fiber breakage, these failure modes interact and expand until the material fracture occurs.

A solid-state electrolyte CaZr0.98−xIn0.02AlxO3−α (x = 0.002, 0.004, 0.006, and 0.008) was prepared using a solid-state reaction method at the temperatures of 1823 K and 1873 K for 10 h. The structures, micromorphologies, and electrical conductivities of these materials were investigated. The results show that CaZr0.98−xIn0.02AlxO3−α has a pure CaZrO3 perovskite phase structure. The electrical conductivities are approximately 1.86 × 10−8–7.13 × 10−6 S/cm at 1073–1273 K, and they significantly increase with increasing temperature under the same atmospheric conditions and gradually increase with increasing water vapor or oxygen partial pressure. This high-temperature proton conductor material would be used as hydrogen sensors of molten metals.

Recompression supercritical carbon dioxide (SCO2) Brayton Cycle for the Chinese Initiative Accelerator Driven System (CiADS) is taken into account, and flexible thermodynamic modeling method is presented. The influences of the key parameters on thermodynamic properties of SCO2 Brayton Cycle are discussed and the comparative analyses on genetic algorithm and pattern search algorithm are conducted. It is shown that the cycle parameters such as turbine inlet temperature, pressure ratio, outlet temperature at the hot end of condenser, and terminal temperature difference of regenerator 1 and regenerator 2 have significant effects on the cycle thermal efficiency. The calculation results indicate that pattern search algorithm has better optimization performance and quicker calculating speed than genetic algorithm. The result of optimization of the parameters for CiADS with supercritical carbon dioxide Brayton Cycle is 35.97%. Compared with other nuclear power plants of SCO2 Brayton Cycle, CiADS with SCO2 Brayton Cycle does not have the best thermal efficiency, but the thermal efficiency can be improved with the reactor outlet temperature increases.

As a potential material applied for thermal barrier coatings (TBCs), the La2(Ce0.3Zr0.7)2O7-3 wt.%Y2O3 (3Y-LZ7C3) coating was deposited by electron beam physical vapor deposition (EB-PVD). To increase the service life of the coatings, the microstructures of the coatings were optimized by adjusting the deposition parameters. The deposition temperature of 930 °C and the rotation rate of 5, 15 and 25 rpm were selected. Due to the different driving forces, the microstructure of the column tips evolved from ‘roof tips’ to pyramids with increasing the rotation rate. There existed a {001} 〈100〉 sheet texture in the coatings deposited at 5, 15 and 25 rpm. In addition, the {001} 〈100〉 sheet texture in the coatings became weak with increasing rotation rate from 5 to 25 rpm. This indicated that the columnar crystals would be synergistically growing during the deposition process. The growth direction of the columnar crystals tended to be more uniform with reducing rotation rate from 25 to 5 rpm. Cyclic life of the coatings was tested at 1050 °C in a heat circulation furnace. The cyclic life tended to be prolonged by reducing the rotation rate from 25 to 5 rpm and the longest cyclic life was 350 h. This gives an approach to the improvement of the service life of TBCs by optimizing the microstructures.

The La 2 (Ce 0.3 Zr 0.7 ) 2 O 7 -3 wt%Y 2 O 3 coating was deposited by electron beam physical vapor deposition (EB-PVD). In order to reveal the structure evolution of the coating with the deposition parameter, the selected rotation rates of the substrate were 0 rpm, 5, 15 and 25 rpm, while the substrate temperature was fixed at 870 °C based on the structure zone model of 0.3 sub /T mp direction. The tips of the ‘roof top’ or the pyramids were covered by four {111} planes. During rotation deposition, the columnar crystal grew along the direction. If one assumes that the pore fraction has little effect on the thermal conductivity, the ‘C’ shaped Type I pores reduced the thermal conductivity, the straight Type I pores increased the thermal conductivity, the lamellar Type II pores significantly reduced the thermal conductivity. The minimum thermal conductivity was 0.761 W/(m K) at the rotation rate of 15 rpm. This gives an approach to optimize the structure of the La 2 (Ce 0.3 Zr 0.7 ) 2 O 7 -3 wt%Y 2 O 3 coatings.

The influences of Er 2 O 3 doping on the structure and thermophysical properties of La 2 Zr 2 O 7 were investigated. The (La 1− x Er x ) 2 Zr 2 O 7 ceramics were synthesized by a solid state reaction method. The XRD results indicate that they all consist of the pure pyrochlore structure. The SEM results show that the microstructure of the sintered ceramics is dense and the grain boundaries are clean. The average thermal expansion coefficients of the (La 1− x Er x ) 2 Zr 2 O 7 ceramics range from 9.57 × 10 −6 K −1 to 9.66 × 10 −6 K −1 . The substitution of Er 3+ for La 3+ effectively reduces the thermal conductivity of La 2 Zr 2 O 7 . With the increasing Er 3+ content, the thermal conductivity significantly decreases at lower temperatures. At higher temperatures, however, the thermal conductivity of the (La 1− x Er x ) 2 Zr 2 O 7 becomes similar, indicating that the thermal conductivity is less sensitive to composition variation. In addition, for the composition with x = 0.10, the thermal conductivity reveals a nearly temperature-independent behavior, which should be ascribed to the strong phonon scattering source (rattlers).

(La 1−2 x Yb x Er x ) 2 Zr 2 O 7 ceramics were synthesized using the solid state reaction method and their thermophysical properties were investigated. All (La 1−2 x Yb x Er x ) 2 Zr 2 O 7 ceramics were composed of the pure pyrochlore phase. The average thermal expansion coefficients of the (La 1−2 x Yb x Er x ) 2 Zr 2 O 7 ceramics ranged from 9.54 to 9.78×10 −6 K −1 . The substitution of Yb 3+ and Er 3+ for La 3+ substantially reduced the thermal conductivity of La 2 Zr 2 O 7 . The thermal conductivity decreased from 2.12 W m −1 K −1 for the composition with x =0 to 1.27 W m −1 K −1 for which with x =0.05 at 26 °C. In addition, the thermal conductivity for the composition with x = 0.05 was less sensitive to temperature variation, which ranged from 1.22 to 1.32 W m −1 K −1 in the measuring temperature range. These results suggested promising potential applications of the (La 1−2 x Yb x Er x ) 2 Zr 2 O 7 ceramics for high temperature thermal barrier coatings.

The influences of equimolar substitution of yttria by gadolinia on the phase constituent and stability for Y 2 O 3 –Ta 2 O 5 –ZrO 2 ceramics have been investigated. The ceramics with the Gd content lower than 8 mol% exhibit pure tetragonal phase as well as high tetragonal phase stability. However, the high Gd containing ceramics consist of t-ZrO 2 , m-ZrO 2 and monoclinic GdTaO 4 and show complicated phase evolution behaviors. The fractions of monoclinic ZrO 2 and GdTaO 4 increase with increasing Gd content, indicating that the excessive substitution of Gd for Y results in a reduction in the tetragonal phase stability. In addition, the lower Gd containing ceramics show an almost invariable tetragonality, while the higher Gd containing ceramics reveal a composition-dependent tetragonality. Accordingly, an association of the tetragonal phase stability and tetragonality with the Gd concentration is established, which provides us a clue to understand the phase stability of these ceramics.

In this paper, single crystal of CuAlNiBe quaternary shape memory alloy was prepared in a high temperature gradient directional solidification furnace with a selective growing crystallizer. And its shape memory performance characters were systematically compared with other series copper base shape memory alloys. The results show that the single crystal of CuAlNiBe quaternary shape memory alloy has better shape memory properties.

The low thermal conductivity, elevated phase-transformation temperature and improved mechanical properties make the ZrO 2 –Nb 2 O 5 –Y 2 O 3 system a promising candidate for thermal barrier coatings. In this study, the influences of the partial substitution of Y 2 O 3 with equimolar Ln 2 O 3 (Ln = Nd, Sm, Gd) on the phase structure and thermal properties of ZrO 2 –Nb 2 O 5 –Y 2 O 3 ceramics have been investigated. X-ray diffraction analysis indicates that these compositions consist of the pure non-transformable tetragonal phase and have an obviously higher tetragonality c / a than the binary ZrO 2 systems. Nevertheless, the partial substitution leads to a decrease in the tetragonality. The thermal conductivity measurement shows that these compositions have low and temperature-independent thermal conductivities, as well as more than 10% reduction in the thermal conductivity due to the partial substitution. Among these rare-earth oxides, Nd 2 O 3 is the most effective oxide for lowering the thermal conductivity. Their thermal conductivities well agree with a point-defect scattering model. The model predicts that the phonon scattering associated with the elastic field around a point defect makes the principal contribution to the reduction of the thermal conductivity for these compositions. This research indicates potential applications of ZrO 2 –Nb 2 O 5 –Y 2 O 3 ceramics for thermal barrier coatings as well as the need for further studies.

With Bridgeman directional solidification method the single crystal alloys of CuAl base shape memory alloy (SMA) with different components were prepared. And their shape memory performance characters were systematically investigated. The results show that the single crystal of CuAlNiBe quaternary shape memory alloy has much better shape memory properties than that of the CuAlBe and CuAlNi ternary alloy. That meant that in the CuAl base SMA alloy the mixed addition of Be and Ni changed the quenching microstructure has a strengthening effect to improve the shape memory performance of the SMA alloy.

In this study, the dependences of yttria content, porosity and grain size on the thermal properties of Y 2 O 3 stabilized ZrO 2 (YSZ) ceramics were investigated. YSZ ceramics were synthesized by the solid state reaction method. The phase, microstructure and thermal properties of YSZ ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and laser-flash apparatus (LFA), respectively. The results indicated that the specific heat capacity of YSZ increased with the increase of temperature and decreased with the increase of yttria content. As the temperature increased, the thermal diffusivity and conductivity of YSZ ceramics were decreased, whereas their variations for 16YSZ, 18YSZ and 20YSZ were much less pronounced than those for 12YSZ and 14YSZ. At a given temperature, the thermal conductivity of YSZ was opposite to yttria content. The thermal conductivity of YSZ ceramics almost linearly decreased with the increase of porosity. In addition, the grain size also had a great influence on the thermal conductivity.

The effects of rare earth oxides on the structure and thermal properties of 8.3 mol.% Y2O3 + 8.3 mol.% Ta2O5 co-doped ZrO2 ceramics were investigated. All compositions consisted of only tetragonal (t) phase when 1 mol.% Ln2O3 was substituted for 1 mol.% Y2O3. The introduction of Ln2O3 into the ZrO2–Ta2O5–Y2O3 system resulted in a decrease in grain growth, specific heat capacity and thermal conductivity. Among these oxides Gd2O3 was the most effective oxide in lowering the thermal conductivity of the ZrO2–Ta2O5–Y2O3 system.

Zr 1− x Gd x O 2− x /2 ( x = 0.08, 0.09 and 0.10) solid solutions were synthesized by solid state reaction at 1600 °C for 6 h in air. These compounds consist of cubic (c) and tetragonal (t) phases. The content of cubic phase increases with the increase of gadolinia doping. Phonon scattering is in accordance with the Umklapp processes. Temperature-dependent variation of the thermal conductivity for cubic phase is much less pronounced than that for tetragonal phase. This indicates that the reduction in total thermal conductivity for Zr 2− x Gd x O 2− x /2 at high temperatures should be mainly ascribed to the decrease of thermal conductivity from tetragonal phase.

WCP/Fe–C composites are manufactured by centrifugal casting method. Dry sliding wear behaviors of the composites containing about 70 vol.% of WCP were investigated at room temperature against 3Cr2W8V die steel counter face. And wear experiments were performed under loads of 50, 100, 150, and 200 N and sliding velocities of 20, 40, 60, and 80 m/s. Results showed that at the low load of 50 N, the composites, under different sliding velocities, all displayed significantly superior wear resistance. Meanwhile the results also showed that the variation of wear weight loss and wear rate of the composites was almost linear with sliding velocity when the sliding velocity and the load were below 60 m/s and 100 N. But as the sliding velocity and the load exceed 60 m/s and 100 N, the weight loss and wear rate of the composites increased rapidly. But the effect of the load applied on wear weight loss and wear rate was larger than that of the sliding velocity. Finally, the mechanism of the dry sliding wear is discussed in the article.

In this paper, single crystal of CuAlNiBe shape memory alloy (SMA) was prepared in a high temperature gradient directional solidification furnace with a selective growing crystallizer. And its performance characters were systematically studied. The results show that the mechanical and shape memory properties of the single crystal of CuAlNiBe SMA alloy has much better than that of the polycrystalline material. This may be explained that the stress concentration at grain boundary caused by the difference of bilateral strains is the dominant reason of deterioration of fatigue properties; therefore single crystal alloy possesses the excellent properties duo to its elimination of grain boundary.

An hBN-Y2O3 composite investment moulding material was developed for investment casting Ti-6Al-4V alloy. Hexagonal boron nitride (hBN) powders plus a few Y2O3 powders were used as the investment mould material to prepare the shell mould with colloidal yttria as binder. The results show that the hBN-Y2O3 composite investment mould can be used to cast Ti-6Al-4V alloy, and has lower cost compared with the traditional yttria based investment mould, because of chemically inert of hexagonal boron nitride and its lower density. Moreover the interfacial reaction between the Ti and hBN-Y2O3 composite shell mould was investigated with measurement of microhardness and scanning electron microscopy (SEM) with energy dispersive (EDS).

Two kinds of thick-walled rings, consisted of WCP/Fe-C gradient composites layers containing about 54 and 70 vol.% of WCP and Fe-C alloy core, were cast by centrifugal casting method. The microstructure, mechanical properties and wear resistance of the gradient composites were investigated. Meanwhile the results were compared with those made of the high speed steel. It was found that WCP in the two kind of gradient composites layers were even well distributed, WCP/Fe-C composites layer of 23-28mm was obtained, the transition layer between the composites layer and matrix alloy core was perfect. The tensile strengths of the two gradient composites layers achieved 345MPa, 460MPa and the impact toughness were 4.6J/cm2, 6.2J/cm2 respectively. Moreover the hardness of the composites layers attained HRA81 and HRA 78. The result of the comparison among the gradient composites layers and that made of the high speed steel showed that the wear resistance of the gradient composites layers containing about 50 and 70 vol.% of WCP was more than 20 times higher than that of the high speed steel under loads of 100N and 200N and sliding velocity of 60 m/s. Finally, the wear-mechanism was discussed.

The effects of Re-Nb on the hardness, tensile strength, Charpy impact energy, and fracture toughness of 3Cr2MoNiWV cast hot working die steel have been investigated. It is shown that the tensile strengths at room temperature and at 600°C increased by 19% and 22% respectively while Charpy impact energy and fracture toughness increased to 109% and 70% respectively while the hardness remain unchanged by Re-Nb modification. The results showed that Re-Nb modification can refine the microstructure of the steel, increase the volume fraction of lath martensite and retained austenite in the tested steel and change the morphology of non-metallic inclusions from bar-like to a fine nodular type. The results are explained based on the modification of the microstructure due to Re–Nb modification.

The in situ composite Cu–Cr alloy, a new type of potential electric material that can be used for contact cables, is reported in this paper. The combination property and thermal stability of the in situ composite Cu–Cr alloy were investigated. Experimental results showed that the in situ composite Cu–Cr alloy has not only high room temperature properties, including ultimate tensile strength σb, elongation rate 5, relative conductivity σr, and combination property that is scaled by M index ( σ b 2 κ r ), but also excellent thermal stability of these properties. At room temperature, the combination property of in situ composite Cu–Cr could be up to 18.3 × 106 MPa2%, which is higher than those of commonly used copper contact cables all over the world. After being heated for 3 h at 500 °C, the combination property of the in situ composite Cu–Cr alloy only decreased 3%. In this paper, the relationship between thermal stability and strengthening mechanism of in situ composite alloy was analyzed.

Sulphur hexafluoride (SF6) is widely used by the magnesium industry as a protective atmosphere. It has been demonstrated that SF6 prevents molten magnesium from further oxidation by reacting with magnesium to make the surface film on the magnesium melt denser. However, due to its high greenhouse effect (GWP=23900), the alternatives of SF6 must be sought. In this paper, 1,1-difluoroethane (commercially named HFC-152a), whose GWP value is only 140 and far lower than that of SF6, was tested to check its capacity of ignition-proof and further-oxidation-proof. Similar to SF6, the melt’s surface film formed in the protective atmosphere containing HFC-152a has a shiny metallic appearance. The surface film’s microstructure has been characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD’s results showed that the film contains only MgO and MgF2 phases while SEM showed their morphologies are uniform.

Melt treatment is one of the most important processes in the production of casting Al alloys. It is also a source of environmental pollution. A green and effective melt treatment with low environmental load (EI), which added with RE (Rare Earth) elements, was investigated in the paper. The research results show that this new treatment can modify, refine and purify the casting Al alloys simultaneously. Compared with the conventional treatment, the process is simplified, the metallurgic quality and mechanical properties are improved, and the environmental pollution which existed in the conventional treatment is solved thoroughly, so represented its wide applicative values.

Effects of the mold rotating speeds on the gradient microstructure and properties of heavy cross-sectional WCP/Fe-C composites made in a self-made centrifugal machine have been investigated with SEM, EDS etc. The results show the ring sample of WCP/Fe-C composites made in a centrifugal machine was free of any defects. And the transition layer between the working layer of WCP/Fe-C composites and matrix Fe-C alloy core was also perfect. The experimental results also show that the WCP-radius-directional distribution in the composites was a continuous component gradient one, which was changed with the various mold rotating speeds. At 1000 rpm the volume fractions of the WC particle from outer layer to inner layer were about 70 vol% to 50 vol% and, at 1400 rpm the volume fractions were about 80 vol% to 65 vol% respectively. The hardness and impact toughness of the working layer of WCP/Fe-C composites were changed with increasing of the mold rotating speeds respectively. Finally, the mechanism of the effects of the mold rotating speeds was discussed in the paper.

In order to get a sound casting of the alloy with a solidification range, the principle of directional solidification (DS) and the layer-by-layer solidification(LBLS) should be followed, especially in designing foundry process of steel casting. Using the principles, the reasons for the forming of the defects on the surface of the chain wheels teeth and groove and the forming of MT (magnetic particle testing) thin lines were analyzed. The results of the metallographic observation and the numerical simulation show that the low temperature gradient results in a wider mushy zone at the S/L interface that causes the defects and MT thin lines on the surface of the chain wheel casting. Based on the analysis, a new casting technology of the chain wheel was designed and used m the casting production successfully.

The effects of rare earth (RE) alloys on the refining and modifying of cast aluminum alloys were investigated. Compared to other substances in common use, rare earth alloys maintain the refining and modifying effects of the aluminum alloys for a longer time. RE alloys can also reduce environmental pollution in the melting process. These effects of RE alloys make them become a superior choice for the applications in aluminum foundry.

Directional solidification continuous casting (DSCC) process is a new manufacturing technology for metallic materials which combines advantages of both directional solidification technology and continuous casting technology. Unlimited long shaped metal with directionally solidifying microstructure can be produced by this process. It is experimentally shown that controlling condition of stable and continuous growth of single crystal structure means the precise control of the location of the S/L interface, which is affected and determined by seven process parameters. Moreover, these parameters are also interacted each other, so the disturbance of any parameters may cause the failure of controlling of S/L interface. In this paper, on the basis of analyzing the forming conditions of continuously directional microstructures in DSCC process, the control model of DSCC procedure by neural network control (NNC) method was proposed and discussed. Combining with the experiments, we first used the computer to simulate the effects of the solidification parameters on destination control variable (S/L interface) and the interactions among these parameters during DSCC procedure. Secondly many training samples necessary for neural network calculation can be obtained through the simulation. Moreover, these samples are inputted into neural network software (NNs) and trained, then the control model can be built up.

The effect of rare earth (RE) elements on the morphologies and sizes of Si phases in the hypereutectic Al-Si alloys modified with P was investigated. The results show that the addition of La element to the hypereutectic Al-Si alloys can enhance the effect of P element on the modification of the primary Si phases. In the multiplex modification of RE-P, the primary Si phase is refiner and the shape of the eutectic Si is changed from long needle-like to short rod-like. Moreover, the agglomeration rate of the primary Si phase is slowed greatly. Even the melt is held for 6 h, the average size of the primary Si phase is still satisfied. The results analyzed by scanning electron microscope (SEM) indicate that La is richer at Al-Si interface than that in α-Al or primary Si phase. The higher the La content in the Al-Si interface, the smaller the primary Si phase.

For in-situ composite materials, the interaction between the second-phase particles and the solidification interface attracts more attentions of people, for concerning the final distribution of the particles on the matrix. With the conception of the local solidification time, a kinematics mechanism of particle pushing into the crystal boundary during the solidification process was assumed. Through the analysis of forces acted on the particle in front of the solid/liquid interface the critical velocity criterion for the particles pushing was given. The calculation results show when the growth rate of the interface V is less than or equals to the critical velocity V c , the particles on the solid/liquid interface is pushed into the boundary region of cellular crystals, where they are distributed as a chain-like straight, which forms a particle-strengthened in-situ composite materials.

The production of common sintered brick by using waterworks sludge and fly ash as major raw materials with the addition of feldspar powder and quartz sand is studied. The apparent natures, compressive strength, water absorption and other performance tests of the bricks are investigated. The results indicate that 60%-70% of waterworks sludge can be used to produce common sintered bricks. The water absorption is about 20% and the compressive strength is higher than 20MPa, which meet the National Standards(GB/T5101-2003).

With the organic combination of melt supercooling and directional solidification techniques, a new concept of rapid directional solidification excited from supercoded melt has been advanced. In this paper, the experimental method of this new technique is reviewed. The difference between the new and the conventional directional solidification processing is illustrated diagramatically. The latest experimental results are given for Cu Ni alloy, which indicate the attractive prospects of the new technique.