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According to the basic principles of electromagnetism, the magnetic flux density on the surface of the metal melt was calculated by numerical simulation method. The relational expression of the electromagnetic body force and the magnetic flux density was deduced. The results show that the electromagnetic body force in the melt is directly proportional to the square of the magnetic induction intensity. Increasing the electric current, the electromagnetic body force in the melt can be increased effectively. Increasing the frequency, the particular electromagnetic body force within the melt can be increased first and then decreased.

Based on the direct reduction alloying theory, the kinetics investigations on process of direct smelting and alloying between high-carbon ferrochrome and molybdenum were conducted. The results indicate that at the high temperature MoO3(g) can easily reduced by carbon dissolved in iron liquid. Reducing the volatilization loss of MoO3is the most effective measure to increase the Mo yield. With regard to the reaction between CaMoO4(l) and dissolved carbon at steelmaking temperature, the increases of mass transfer coefficient of CaMoO4in slag and phase contact area between metal and slag make for increasing the reduction rate. CO gas generated from extra carbon acting as reducing agent can provide favorable kinetics conditions for reduction reaction. The reaction between Cr7C3(l) and MoO3(l) in liquid steel is similar to the reaction between CaMoO4(l) and dissolved carbon. The incensement of mass transfer coefficient of MoO3(l) in slag can improve the reduction rate effectively. The CO gas generated from reaction can stir molten bath promote foam slag formation, so as to increase the phase contact area, which provides favorable kinetics condition.

A thermodynamic model of calculation of sulfur distribution ratio between B2O3-containing slag and molten steel has been developed on the basis of the ion and molecule coexistence theory. Based on the model, the effects of B2O3 content and slag basicity on the sulfur distribution ratio in 1873K were investigated respectively. The results indicate that the sulfur distribution ratio decreased with increasing the content of B2O3, and when the content of B2O3 exceeds 6%, the sulfur distribution ratio was lower than 2.0. Therefore, in order to ensure the desulphurization ability of slag, the content of B2O3 should be controlled at about 6%. Moreover the sulfur distribution ratio can be increased by increasing the slag basicity.

Based on the direct reduction alloying theory, experiments on chromium molybdenum alloy prepared through the direct reduction and alloying reactions between the high-carbon ferrochrome and molybdenum oxide were conducted in a laboratory scale. The critical factors that would impact the reduction rate of molybdenum oxide and the yield rate of molybdenum were analyzed. The results indicate that the reduction rate of molybdenum oxide can exceed 90%, meanwhile, the yield rate of molybdenum is affected by many factors and fluctuates in a wide range. As temperature rising, the reduction rate of molybdenum oxide is increased whereas the yield rate of molybdenum is decreased. With the amount of molybdenum oxide added increasing, the reduction rate of molybdenum oxide and yield rate of molybdenum are decreased simultaneously. Making slag during melting process and molybdenum oxide roasted by addition of lime are effective measures to improve the yield rate of molybdenum.

Nanometer Al2O3 particles reinforced 7055Al composites were processed by high magnetic field with 2T,3T and 4T magnetic induced intensity (B) with constant 30 pulses. Transmission Electronic Microscopy (TEM) and X ray diffraction (XRD) were mainly used to analyze some characteristic of the treated samples. The results show that with the increase of B the dislocation density was enhanced apparently. It is deduced that plastic deformation was the main reason of high density dislocation. The magnetoplasticity effect was the source of plastic deformation.

In the TC4 titanium alloy subject to high pulsed magnetic field, the phase transformation from α to β occurs. When the magnetic induced intensity increased from 2T, 3T to 4T with constant 30 pulses, the percent of α phase adds up gradually. When the magnetic induced intensity is 4T the volume fraction of α phase amounts up to 59%. It is ascertained that magnetic field has taken a positive influence on the phase transformation because of the variation of inner energy induced by magnetic field.

Nanometer Al2O3 particles reinforced Al-Zn-Mg-Cu composites were processed by cryogenic treatment with different cycle index of 1,2 and 3. Transmission Electronic Microscopy (TEM) was utilized to analyze the microstructural evolution of the treated samples. The results show that with the increase of cycle index the precipitate amount and dislocation density have been increased. The precipitates orientation exhibits some preferred orientation. The high amount of precipitates and dislocation density and preferred orientation of precipitates will benefit to increase the mechanical properties of composites.

Al3Ti and Al3Zr particles reinforced 7055Al composites were processed by cryogenic treatment with different cooling speed at 1°C/min, 3°C/min and 5°C/min. Transmission Electronic Microscopy (TEM) was mainly used to analyze the microstructural evolution of the treated samples. The results show that with the increase of cooling speed the precipitate amount and dislocation density have been increased. The precipitates orientation exhibits some preferred orientation. The mechanical properties test demonstrates that for the samples treated at 5°C/min the tensile strength and elongation has arrived at the utmost.

The melting temperature of CaO-SiO2-B2O3-(boron mud, CaF2) slag system was investigated. The slag melting temperature was measured by using the hemisphere method. The results indicate that B2O3 has a significant fluxing effect on the slag system. When 1%-11% B2O3 was employed as fluxing agent, the melting temperature of the slag changed from 1525°C to 1200°C. When the content of B2O3 is 5% and the range of basicity is 1.5~3.5, the melting temperature of the slag increases with the increase of the basicity. However, when boron mud or CaF2 was added to the slag, the melting temperature of the slags decreased with the increase of addition at a fixed B2O3 content (5%) and a fixed basicity (R=2.5). Furthermore, the melting temperature of the slag system which contains CaF2 is lower than the slag system which contains boron mud.

Under the condition of different magnetic induced intensity as1.5T, 2.0T and2.5T, AlTiZr particles reinforced 7055 aluminum matrix composites were subject to the magnetic impact processing. The structural evolution was observed by transmission electron microscope. The result shows that, magnetic impact processing can induce dislocation with different morphologies and increase the dislocation density. The enhancement of dislocation density and elastic interaction between them can cause the resistance of dislocation movement and improve the strength of material. The magnetic pressure may exceed the yield strength of special orientation crystal. The increased temperature induced by heat effect will lower the yield point further. It is useful to dislocation nucleation and movement.

To reduce the pollution caused by employing CaF2 as fluxing agent in metallurgical flux, boron sludge is used as fluxing agent to substitute for CaF2. The melting temperatures of CaO-SiO2-Fe2O3-boron sludge system were investigated. The melting temperature of CaO-SiO2-Fe2O3-boron sludge slag system is increased with the increase of ω (CaO)/ω (SiO2) at first, and then fluctuates at about 1430°C. Moreover, the melting temperature of CaO-SiO2-Fe2O3-boron sludge system is decreased with the increase of boron sludge content at first and then increased, 7% content of boron sludge has the best fluxing effect and the melting temperature is1445°C. As a conclusion, the fluxing effect of boron sludge is close to CaF2, boron sludge may be considered to substitute for CaF2.

The correlation between the deformation behavior and the microstructure of AZ31 magnesium alloy processed by as-extruded and ECAP is investigated in this paper. The grain size of as-extruded AZ31 magnesium alloy is about 30μm which dues to basal and twinning. Twinning is the main deformation behavior for as-extruded AZ31 magnesium alloy. The deformation of as-extruded is mainly caused by basal slip and twinning. The grains of ECAP are further refined to 6μm. With little amount of twins, the refinement of AZ31 magnesium alloy is caused by non-basal sliding. For ECAP precessed sample, grain boundary sliding happens and the proportion of high-angle grains are improved, which makes grain boundary sliding easier. The main deformation mechanism of ECAP is non-basal slip and grains boundary sliding.

7055 aluminum alloy was processed by circular cryogenic-aging treatments for four times. Some characters such as precipitates, dislocation density, crystal structure and micro hardness were studied in detail. It is showed that the sizes of precipitates are decreased from several hundred nanometers to 100nm with the increase of cycle index. The main components are AlZn or AlZnMg phases. The hardness test result illustrates that the micro hardness arrives at 232HV after circular cryogenic-aging treatment for twice. The corresponding precipitates exhibit high density and complex sizes. The sizes are in the range of 50-200nm.

The thermodynamic condition and behavior of precipitates were discussed about the Al2O3 p/7055 composites subjected to cryogenic treatments. A kind of software named Thermo-Calc was employed to calculate and analyze the mass amount of several main precipitates based on the thermodynamic balance theory. The results demonstrate that when the temperature decreases from 300K to 77K the precipitated amount of T(AlZnMgCu) and θ (Al2Cu) phases will increase. For S(Al2CuMg) phase, at 175K there is a transverse point from increasing tendency to the opposite. It should be noted that η (MgZn2) is the main precipitated phases in compistes ,which accounts for more than eleven weight percent in one mole material. But the balance mass amount lower a little from 300K to 77K. It is analyzed that the volume shrinkage and lattice contract are the main driving forces for precipiting. Due to the difference of heat expansion coefficient among various phases the anisotropic shirinkge lead to micro voids that will act as the nucleation cores,which faciliate the precipitation.

In Mg-Al alloy β (Mg17Al12) phase is the main precipitate and reinforced phase. The microstructure and performance of alloy are strongly dependent on the morphology and behavior of β phases. In this paper, a kind of Mg-Al alloy is chosen as the research object with 8.92 weight percent aluminum element. The alloy is subjected to cycling cryogenic treatment. The microstructure evolution and thermodynamic balance are analyzed by scanning electronic microscope and Thermo-CALC software. The results show that after two cryogenic treatments the quantity of the precipitate hardening β phase increases and the sizes of the precipitates are refined from 8~10 μm to 2~4μm. This is expected to be due to the decreased solubility of aluminum in the matrix at low temperatures and the significant plastic deformation due to internal differences in thermal contraction between phases and grains.

According to the coexistence theory of melted slag structure, a calculation model of mass action concentrations for CaO-B2O3-SiO2 slag system has been established, by which the mass action concentrations of all structure units in CaO-B2O3-SiO2 systems are calculated. The results indicate that the activities of CaO and 2CaO•SiO2 can be decreased effectively by B2O3. Furthermore, when the slag basicity is higher than 2.0, the activity of 2CaO•SiO2 increases firstly and then decreases with the increasing of B2O3 content. The activity of CaO increases with the increasing of slag basicity. When the basicity is less than 2.2, the activity of 2CaO•SiO2 increases with the increase of slag basicity. Moreover, when the basicity is 2.2, the activity of 2CaO•SiO2 reaches the maximum value. In another word, the activity of 2CaO•SiO2 decreases with the increase of slag basicity on the condition that the slag basicity exceeds 2.2. B2O3 exists in the slag in the form of CaO•B2O3, 2CaO•B2O3 and 3CaO•B2O3.

A mathematical model on activities of CaO-based slag system has been established on the bases of ion-molecule coexistence theory of melted slag structure. The activities of CaO-SiO2-B2O3 (Al2O3, Fe2O3) systems are calculated. The effects of the content of B2O3, Al2O3 and Fe2O3 on activities are analyzed. The results indicate that the activities of CaO and 2CaO•SiO2 are decreased with the increases of B2O3, Al2O3 and Fe2O3. The effect of B2O3 is most remarkable. Moreover, the activity of CaO•SiO2 can be enhanced with increasing the contents of B2O3, Al2O3 and Fe2O3 respectively. These effects of Al2O3 and Fe2O3 are very similar, whereas the effect of B2O3 is most significant. As a conclusion, B2O3 is most effective to inhibit the formation of 2CaO•SiO2 as well as to promote the dissolution of lime.

new flux method is explored to decrease the reactive temperature of in situ chemical reaction to fabricate particles reinforced aluminum matrix composites. When B2O3 flux is added into the mixed reactive salts the melting points of them decrease with the increase of adding amount of B2O3 in the range of 1-5wt.%. When w(B2O3)=5% the melting point of K2TiF6-B2O3 salt is 450°C,which is decreased by 90°C compared with that of pure K2TiF6. Meanwhile the in situ reactive time is shortened and the actual volume fraction is increased.

According to the coexistence theory of melted slag structure, a calculation model of mass action concentrations for CaO-Al2O3-SiO2 slag system has been established, by which the mass action concentrations of all structure units in CaO-SiO2-Al2O3 systems are calculated. The effects of Al2O3 content and slag basicity on the mass action concentrations are investigated. The results indicate that both basicity and the content of Al2O3 have remarkable effects on mass action concentrations of CaO, 2CaO•SiO2, CaO•SiO2, CaO•Al2O3 and 2CaO•SiO2•Al2O3, etc. Furthermore, the effects of Al2O3 content on mass action concentrations are relevant with slag basicity. The basicity has more influences on mass action concentrations of CaO, CaO•SiO2, 2CaO•SiO2 and 3CaO•SiO2, whereas the basicity has little effect on mass action concentrations of other structure units in CaO-SiO2-Al2O3 system.

The melting temperatures of CaO-(2CaO•SiO2)-B2O3-SiO2-(Al2O3) slag system were investigated. The results indicate that B2O3 has significant fluxing effect on this slag system. When the content of B2O3 is about 10% in these slag system, the mass ratios of w(CaO)/w(SiO2) and (CaO)/w(Al2O3) can be controlled in the scope of 1.5-8.0, the melting temperature of slag is still lower than 1340°C, which is suitable for steelmaking and secondary refining process. As a conclusion, when 10% B2O3 is employed as fluxing agent, a kind of CaO-based slag system with ultra-high basicity, ultra-low alumina content as well as low melting temperature can be obtained.

B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3 steelmaking slags to substitute for CaF2. The influences of B2O3 and CaF2 on the melting properties of this system slags were investigated and compared. The results indicate that the fluxing effect of B2O3 is more remarkable than that of CaF2. Therefore, B2O3 promotes the dissolution of CaO, SiO2 and 2CaO•SiO2, etc, then the slagging speed can be improved greatly. The melting temperatures of slags increase with the increasing of basicity, especially, when CaF2 is used as fluxing agent as well as the basicity is up to 5.0, the melting temperature is increased higher than 1420°C. These characteristics of boron-containing slgas are more suitable for steelmaking process than those of fluoride-containing slags.

Al2O3，Al3Ti and Al3Zr particles reinforced 7055 aluminium matrix composites were fabricated via melt reaction method. The volume fraction is controlled at about 4-5%. After extrusion and solution-aging heat treatment the sample was prepared for deep cryogenic treatment, The microstructure and evolution of mechanical properties of (Al3Ti+Al3Zr)p/7055 composites were analyzed using optical microscopy(OM),scanning electronic microscopy(SEM) and X-ray diffraction(XRD). Some θ(Al2Cu) phases with nanometer size precipitate in the inner grain. As some grains preferred orient the intensity of some main diffraction peaks increase. Compared with those of as-cast and squeezed states the micro hardness has increased by 16.8% and 10.0% separately.

For the elimination of the fluorine pollution of steelmaking slag, boron mud is employed as fluxing agent for CaO-based fluorine-free slag. The effect of boron mud on the melting properties of slag is investigated. Hemisphere method is used to determine the melting temperature of samples. The results indicate that when the content of boron mud is lower than 7%, the melting temperature can be decreased by boron mud. With the content of boron mud increasing higher than 7%, the melting temperature is increased with increase of boron mud content. The basicity and the content of F2O3 have remarkable effect on the melting temperature of boron mud containing slag. When the basicity is in scope of 2.0-5.0, the melting temperature is in the range of 1350-1450°C correspondingly. The melting temperature of boron mud containing slag can be decreased significantly with increase of F2O3 content.

B2O3 is used as fluxing agent of converter slag to substitute for CaF2 so as to reduce fluorine pollution and decrease the melting temperature. Hemisphere method is used to measure the melting temperature of samples. Effect of ω(CaO)/ω(SiO2), content of Fe2O3 and content of B2O3(CaF2) on the melting temperature of CaO-SiO2-F2O3-B2O3(CaF2) system have been studied. Results indicate that the melting temperature of samples are decreased when B2O3 substitute for CaF2 equally with equal ω(CaO)/ω(SiO2) and content of Fe2O3 [ω(CaO)/ω(SiO2)=1.5~5.0, Fe2O3=0~30%], the melting temperature of samples are decreased remarkably with the increase of content of B2O3 [ω(CaO)/ω(SiO2)= 2.5].

Based on the coexistence theory of slag structure, the activity model of CaO-SiO2-Fe2O3 ternary slag system was established. The effects of Fe2O3 content and basicity on the activities of CaO and 2CaO•SiO2 were investigated. The structure units of Fe2O3 in the molten slag were discussed. The results indicate the slag basicity has a significant influence on the activities of CaO and 2CaO•SiO2. The activity of CaO increases with increasing slag basicity, while the activity of 2CaO•SiO2 increases with the increasing of slag basicity when the basicity is less than 1.8, which reaches the maximum value when the basicity is 1.8. In another word, when the slag basicity exceeds 1.8, the activity of 2CaO•SiO2 decreases with the increasing of slag basicity. In addition, the activities of CaO and 2CaO•SiO2 can be decreased by Fe2O3. Moreover, when the slag basicity is higher than 2.0, the activity of 2CaO•SiO2 increases slightly with the increasing of Fe2O3 content. The main structure units of Fe2O3 in molten slag are closely related to the slag basicity.

TiB2/Al composites were prepared by the direct melt reaction using Al-3B master alloy and Ti powder as the reactive materials. The phase composition and the microstructure of the as-prepared composites were investigated by XRD, SEM, TEM etc.. It is showed that the reinforcement was only TiB2, moreover, the volume fraction of the reinforcements increased with the increasing of the reactants. The TEM images showed that TiB2particle was in the shape of hexagonal, circle and rectangle, and its size was 0.5-2μm.

The K2TiF6,K2ZrF6powder and aluminum were selected as the raw materials to in situ synthesize the particulates reinforced aluminum matrix composites. During the fabrication process the electromagnetic field was imposed. The atomic ratio of Al/Ti/Zr in the particulates is determined as 3/0.4/0.6. The Al3Ti0.4Zr0.6is a new kind of intermetallic compound, some properties of which fall in between those of Al3Ti and Al3Zr. Electromagnetic field plays an important part in fining particles and promoting their uniform distribution. When the electromagnetic induced intensity is 0.05T the particles have 0.5-2μm average size and uniform distribution in matrix. The crystal grains of matrix resemble equiaxed ones. The average size of grains are nearly 100μm, 50μm and 25μm when the electromagnetic induced intensities are 0, 0.025T and 0.05T seperately.

According to the rule of non-sinusoidal oscillation of continuous casting mold, a mathematical model was established to study the effects of oscillation parameters on the consumption rate of mold flux. The results indicated that the mold flux consumption rate is remarkably affected by the non-sinusoidal factor. This proves that the non-sinusoidal oscillation of mold contributes to increase the flux consumption. Moreover, the amplitude and frequency of mold oscillation have effects on mold flux consumption rate. The non-sinusoidal oscillation parameters must be optimized.

(Al2O3+Al3Zr)P/Al composites were in situ synthesized from Al-Zr(CO3)2system. In the process of in situ reaction, electromagnetic stirring (EMS) is employed to improve the conditions of reaction between reactants powder and melt. The results indicate that the Lorenz force improves the kinetic condition and accelerates the nucleation of endogenetic particulates. The optimized electromagnetic density is 0.025T. Scanning electronic microscope (SEM) observation demonstrates that the sizes of reinforced particulates are controlled at 1~2μm. Moreover, the particulates are well distributed in Al matrix.

(Al3Ti)p/6351 composites were in situ synthesized via direct melt reaction between 6351 wrought aluminum alloy and K2TiF6 at 720°C. OM, SEM and EDS are utilized to analyze the microstructure and components of composites. The fusing agents of CaF2 and LiCl are mixed with K2TiF6 to lower the temperature of initial in situ reaction. The volume fraction of Al3Ti is 3%.The size of Al3Ti is in the range of 2~4μm, which is much lowered than that fabricated by conventional process. Due to the calcium element from CaF2 the size of Mg2Si phases are decreased to 1~2μm.The microns of independent silicon phases are also observed in the squeezed section. The grain size of α-Al is fined to 30~40μm, which is due to the disperse effect of Al3Ti. The tensile, yield properties and elongation are at room temperature are 365MPa, 320MPa and 10.2%.