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Recently, Ni-free shape memory Ti-based alloys (composed of the biocompatible β-stabilizing elements such as Ta and Nb) are extensively studied. In this work, new Ni-free Ti-17Nb-6Ta is presented as a candidate for shape memory alloys with high biocompatibility. This alloy produced using arc-melting in argon atmosphere, followed by solution annealing at 900° C for 30 min. β-phase is the predominant phase beside α” martensite phase. Stress induced martensitic transformation is observed after cold rolling and during bending tests as measured by XRD. The hardness of the bended wire in the solution treated condition was around 330HV. While the cold rolled wire hardness before bending was 300 HV. The superelasticity and shape memory effect was investigated through bending tests of alloy wires. The cold rolled wire showed higher superelasticity than shape memory effect. But superelasticity and the shape memory effect were almost similar with the solution treated wire. Also, the total spring back in cold rolled wire is higher compared with solution treated wire.

The aim of this work was to study the effect of milling time on binary magnesium-titanium (Mg-Ti) alloy synthesized by mechanical alloying. A powder mixture of Mg and Ti with the composition of Mg-15wt%Ti was milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Milling process was carried out at 400 rpm for various milling time of 2, 5, 10, 15 and 30 hours. 3% n-heptane solution was added prior to milling process to avoid excessive cold welding of the powder. Then, as-milled powder was compacted under 400 MPa and sintered in a tube furnace at 500 °C in argon flow. The refinement analysis of the x-ray diffraction patterns shows the presence of Mg-Ti solid solution when Mg-Ti powder was mechanically milled for 15 hours and further. Enhancements of Mg-Ti phase formation with a reduction in Mg crystallite size were observed with the increase in milling time. A prolonged milling time has increased the density and hardness of the sintered Mg-Ti alloy.

A layer of Mo (Si,Al)2 was prepared on the sample surface of Mo substrate by powder coating method using Al-Si mixed powder and then diffusion reaction in argon atmosphere at 900°C. The results of oxidation resistance showed that the Mo samples coated with the Mo (Si,Al)2 layer had an excellent oxidation resistance in air even at 1200°C. The reason of oxidation resistance is the formation of a dense alumina film on the sample surface. Therefore, the further oxidization of the sample can be prevented. In addition, The formation of Mo5(Si,Al)3 layer was also observed at the interface between the Mo substrate and the Mo (Si,Al)2 layer.

The paper presents experimental results regarding the evolution of hardness and impact energy of some sintered steels alloyed with 1.5% respective 3% (weight) copper powders. For the experimental research were used 3 mixtures: Fe+0.2C as reference, Fe+0.2C+1.5Cu, Fe+0.2C+3Cu. All the samples were die pressed at three pressures 400, 500 and 600 MPa and were subjected at three types of treatments as following: SINT, SINTCARB and CARBSINT. For the sintering treatments was used argon atmosphere and for carburizing process was used methane. After each treatment the hardness and impact energy for all the samples were measured and were made correlations between these properties and the type of treatment and copper content.

Iron (Fe)-tin (Sn) intermetallics were synthesized by using two different routes. These two routes had a common synthesis step, in which Fe powder (19 wt. %) was mechanically alloyed with Sn powder (81 wt. %) for 25 h under argon atmosphere. The mechanically alloyed powders were then treated with different heating routes. In the first route, the compacts of the mechanically alloyed powders were sintered at different temperatures for different times. It was found that the FeSn2 content increased with increasing temperature and time. There were small traces of Fe, Sn and FeSn found in the sintered materials. In the second route, the mechanically alloyed powders were plasma-sprayed using different currents of 300, 400 and 500 A. It was found that the porous coatings produced by plasma sprayng consisted of mixed Fe, Sn, FeSn2, SnO, FeO and Fe3O4 for all employed currents.

The SmCo5has three sintering stages using spheres (0.6 – 1.0 mm diameter) at temperatures between 1030 and 1200 °C. During the first stage the neck radius increases as X2~ t for less than 1200 °C temperature, the exponent is 3 at 1200 °C. Interdiffusion is sintering mechanism for exponent of 2. Sm diffuses from inside to the surface, where it is oxidized and oxides fills the neck between the spheres. Co diffuses through the oxides. At 1200 °C the sintering mechanism is evaporation-condensation of Sm. The activation enthalpy of the first stage is 582 kJmol-1for temperatures above 1130 °C and 210 kJmol-1bellow 1130 °C, respectively. The second stage is characterized by a plateau where the neck growth is arrested. The small pores in the neck and in the sphere surface layer (formed during the first stage) shrink. When these pores disappear a continuous α-Co layer forms and the third stage starts. It is essential growth of the neck formed by dense Co layer. The law of sintering is X4~ t. The activation enthalpy (276 kJmol-1at temperatures above 1130 °C) closes the activation enthalpy of Co self-diffusion. This (together with the exponent of 4) suggests that the Co layer plays a role similar to that of a liquid film. Making slight changes in the chemical composition of the alloys and substituting an argon atmosphere to vacuum have no influence or stages and sintering mechanisms.

Mechanical alloying (MA) is used to prepare amorphous alloy powders. The experiments were performed by a high energy ball milling device using stainless steel vessels and balls under argon atmosphere at a rotation rate of 450 r/min. B and Y were used as the minor additions to prepare new quaternary or complex amorphous alloy powders. Ti50Al(47-x-y)Zr3BxYy(x=0, 0.6, y=0, 0.2) amorphous alloy powders were successively obtained. The milled amorphous alloy powders were characterized by XRD, SEM and DSC. Ti50Al47Zr3amorphous alloy powders were obtained after milled 50h. The milling time needed to obtain complete amorphous alloy for Ti50Al46.4Zr3B0.6, Ti50Al46.8Zr3Y0.2and Ti50Al46.2Zr3B0.6Y0.2are 40h, 35h and 30h, respectively. Minor additions of B and Y decreases the milling time for preparing amorphous alloy. SEM shows that B and Y can refine the grain of the amorphous alloy powders. DSC shows that minor substitution of 0.6at.%B or 0.2at.%Y can increase the glass forming ability (GFA) for the TiAl based alloys.

The paper presents results of research into the aluminizing process of TiAl intermetallics. The substrate was Ti48Al2Cr2Nb intermetallic alloy. The BPX Pro 325S CVD system was used for aluminizing process. Used in the experimental were four types of activators: AlCl3, AlF3, ZrCl4and HfCl4. During the aluminizing process 2 kg of Al-Cr granules were put in a container. The deposition process was carried out in argon atmosphere for a duration of 4 hours at the temperature of 1000°C. The XRD and chemical analysis were conducted. The results showed than aluminide coatings contained TiAl2and TiAl2phases were formed using an AlF3activator. In other processes the amount of Al in the coatings was smaller than in the substrate. The obtained results showed that for the aluminizing process use of aluminum fluorides is necessary.

Zirconium diboride (ZrB2) powders were synthesized by sol-gel carbonthermal reduction method using zirconium oxychloride (ZrOCl2·8H2O), boric acid (H3BO3), source (C12H22O11) and citrate (as chelation agent). The Zirconium diboride precursors were calcined at 1600¡æ for 2h, 3h and 4h under argon atmosphere. The precursors and sintered samples were characterized by TG-DSC, XRD and SEM. Results revealed that the ZrB2powders prepared at 1600°C for 4h exhibited quasi-tabular morphology with a small average crystalline size about 20μ. With respect to the conventional solid state method, the Sol-gel method route guaranteed a faster, easier and energy-saving process for obtaining nanopowders.

The plasmodynamic synthesis was conducted in the electric hypervelocity pulse jet of carbon-silicon electric discharge plasma influenced on a copper target in an argon atmosphere. Some samples of a powder product with a high content of β-SiC were produced. The results of the experiments made at different levels of supplied energy were compared. It was shown that the sizes of crystals grew, when the energy of a plasma shot increased.

Electric furnace for thermal treatment to recover valuable materials from spent batteries was newly designed to enhance it with safe, efficient, and eco-friendly processes. Spent batteries were handled in the furnace at 500°C for 2 hours under argon atmosphere and they were found to be separated in side reactor with easy. The electrodic powder including valuable metals such as Mn, Ni, Co, Zn, etc. was recovered from bulk components through sieving process.

Continuous-type electric furnace for thermal treatment to recover metal values from waste mixed batteries was newly developed to enhance it with safe, efficient, and eco-friendly processes. Waste mixed batteries were charged continuously into the reactor and handled in the furnace at 500°C for 2 hours under argon atmosphere and they were found to be separated in side reactor with easy. The electrodic powder including valuable metals such as Mn, Ni, Co, Zn, etc. was recovered from bulk components through sieving process.

Ti-Fe alloy is prepared by the electrolytic reduction of titanium concentrate in molten CaCl2 under argon atmosphere. The formation mechanism of Ti-Fe alloy is discussed. The impact of electrolytic time on product is studied when electrolytic voltage is 3.1V and electrolytic temperature is 900°C. Results show that Ti-Fe alloy with uniform composition can be obtained by this method. The deoxidize product is iron and TiFe alloy by order. The reduction of Ti is a multi-step process and the intermediate products include CaTiO3,TiO2, Ti2O3, TiO,Fe, TiFe2.

The Al2M3Y(M=Cu, Ni) compound was synthesized by arc melting under argon atmosphere. The high-quality powder X-ray diffraction data of Al2M3Y have been presented. The refinement of the X-ray diffraction patterns for the Al2M3Y compound show that the Al2M3Y has hexagonal structure, space groupP6/mmm(No.191), with a = b = 5.1618(2) Å, c = 4.1434(1) Å,V= 95.6 Å3,Z= 1,ڑx= 5.7922 g/cm3,F30= 155.5(0.0057, 34), RIR = 2.31 for Al2Cu3Y, and with a = b = 5.0399(1) Å, c = 4.0726(1) Å,V= 89.59 Å3,Z= 1,ڑx= 5.9118 g/cm3,F30= 135.7(0.0072, 30), RIR = 2.54 for Al2Ni3Y.

New titanium alloys for biomedical applications have been developed primarily with the addition of Nb, Ta, Mo, and Zr, because those elements stabilize the β phase and they don’t cause cytotoxicity in the organism. The objective of this paper is to analyze the effect of molybdenum on the structure, microstructure, and selected mechanical properties of Ti-15Zr-xMo (x = 5, 10, 15, and 20 wt%) alloys. The samples were produced in an arc-melting furnace with inert argon atmosphere, and they were hot-rolled and homogenized. The samples were characterized using chemical, structural, and microstructural analysis. The mechanical analysis was made using Vickers microhardness and Young’s modulus measurements. The compositions of the alloys were sensitive to the molybdenum concentration, indicating the presence of α’+α”+β phases in the Ti-15Zr-5Mo alloy, α”+β in the Ti-15Zr-10Mo alloy, and β phase in the Ti-15Zr-15Mo and Ti-15Zr-20Mo alloys. The mechanical properties showed favorable values for biomedical application in the alloys presenting high hardness and low Young’s modulus compared with CP-Ti.

The Mg2Si compound was synthesized by the solid state reaction method. The powder precursors of Mg and Si were thoroughly mixed in ballmilling for 24 hr in an argon atmosphere. Mixed powder was pressed at 170MPa and sintered at 800 °C for 6 hr in an argon atmosphere. The sinter powder was crushed in mortar for 1 hr. The crystal structure and microstructure were measured and observed by using XRD and SEM. The microstructure and the crystal structure were analyzed. TheMg2Si shows single phase, cubic structure and particle size about 1-10 mm.

F-75 (Co-Cr-Mo) alloy are widely used in the production of medical implants because of their excellent strength properties, hardness and also one of the biocompatible materials that very suitable in human body environment. In this research, the effect of sintering in terms of sintering temperature and sintering time has been studied by focusing on the microstructure, physical and mechanical properties of F-75 alloy. The samples were prepared by blending the starting material at 160 rpm for 30 minutes, uniaxially pressing at 500 MPa and sintering in an argon atmosphere at two sintering temperatures (1300°C and 1350°C) for four sintering times (60, 90, 120 and 150 minutes). The results show that the grains and bulk density increased with the increasing of sintering temperature and sintering times. However, opposite results were obtained for apparent porosity, hardness and compressive strength

Four high-entropy alloys are prepared by an arc furnace under argon atmosphere. The microstructure and the properties of the alloys are investigated. The results show that NiCrCuCoFe alloy consists of a single FCC solid solution. When Al presents in the alloys, the microstructures of the alloys change to a BCC+ FCC solid solution. It is indicated that Al element promotes the formation of BCC solid solution, and Si and Mn promote the formation of complicated compounds. The hardness of alloys with BCC structure is higher than that of the alloys with FCC structure. The complicated compounds are formed, the hardness increases further. The highest hardness of the alloys reaches 882 HV due to the strengthening of the second phase precipitation.

ZrB2-SiC ceramic composites with the addition of carbon black were fabricated by hot pressed sintering at 1900 °C for 60 min at a uniaxial pressure of 30 MPa in an argon atmosphere. The mechanical properties of ZrB2-SiC ceramic composites were improved, adapting to the use requirements of ceramic parts. The precision electromachining technology of complicated structure components was investigated. The processing surface roughness was evaluated.

Metamict minerals contain radioactive elements that degrade their crystal structure. During the annealing process under ambient pressure in argon atmosphere the sample of metamict rinkite recrystallizes to the primary crystalline form at 700°C. Further heating leads to the formation of a new crystalline phase.

Al8B4C7 ceramic powder was successfully synthesized via a gas-solid reaction method using aluminum, boron trioxide and activated carbon as the starting materials. The effects of synthesis temperature and the amount of B2O3 addition on synthesis of Al8B4C7 were investigated. The results indicated that the optimized process for preparing the Al8B4C7 was that the mixtures were heated at 1800 °C for 2 h in flowing argon atmosphere. With the heated temperature increasing, the Al8B4C7 content was decreased in the products. And 0.5 molar excess of B2O3 addition promoted the formation of Al8B4C7. The heating samples at 1800 °C had a hexagonal plate-like morphology with ~100 μm in size.

The dependence of the layer growth rate on a gas (argon, nitrogen) pressure inside the reactor has been examined in order to analyze the conditions of growth of AlN thick layers and bulk crystals by the sublimation sandwich-method. It is shown that the layer growth rate steadily increases as the pressure in the reactor decreases in a wide pressure interval 1–0.02 bar. This suggests that a key role in the layer growth kinetics is played by the source-to-substrate transfer of the components (Al, N), rather than the adsorption - desorption processes on the source and substrate surface. In addition the growth rate in argon atmosphere is much higher than in nitrogen one for the high pressures and is practically the same for the lowest (0.05 – 0.02 bar).

Highly ordered TiO2 nanotubes were successfully prepared via a facile anodization method in ethylene glycol and water mixture electrolyte (99 vol% EG + 5 wt% NH4F). The as-anodized TiO2 nanotubes were crystallized by annealing at 400 °C for 4 hours in argon atmosphere. A series of phosphorus incorporation with different phosphorus content have been prepared by soaking TiO2 nanotubes samples in H3PO4. The photocatalytic activity of TiO2 nanotubes and P-incorporated TiO2 nanotubes were evaluated by the photodegradation of methyl orange. It was found that the photocatalytic activity of P-incorporated TiO2 nanotubes was 34% higher than TiO2 nanotubes.

A new processing concept has been developed to produce nano structured metal matrix composite coatings. Electroless coatings of Ni-P and composite Ni-P-ZnO were developed by co-deposition process on mild steel substrates. Ni-P-ZnO coatings were prepared using conventional route i.e., ZnO particles of ~ 20 μm with average diameter were added to the bath (900C, pH ~9.0) and kept in suspension by stirring. Uniform and grayish bright coatings were observed. The coatings were heat treated at 400°C for 1h in argon atmosphere to attain crystalline nature of coating. The as-synthesized and heat treated Ni-P and composite Ni-P-ZnO coatings were characterized by XRD, FESEM and AFM.

One suitable material candidate to improve B4C mechanical properties is SiC. B4C-SiC ceramic composites are very promising armor materials because B4C and SiC are intrinsically very hard. In this work a pressureless sintering study of B4C-SiC ceramics was made. B4C-SiC mixtures were prepared with SiC concentration from 10 to 50 wt%. Without the external applied pressure during sintering it was necessary to add sintering aid. The additive system AlN-Y2O3 was investigated as sintering aid. Samples were densified by pressureless sintering at 2000 °C/30 min in an argon atmosphere. B4C-SiC composites were analyzed by XRD and SEM. Bulk density and total weight loss were also measured. Density higher than 93 % of the theoretical value was determined and microhardness of 30.3 GPa was achieved for composite with 10 wt% of SiC sintered with AlN-Y2O3 additive.

In order to find out the optimum thermodynamic conditions for hot metal dephosphorization and predict phosphorus content after demanganization pretreatment, thermodynamic equilibrium experiments between CaO-FetO-SiO2-MnO-P2O5 slag and silver/solid iron were carried out in an iron crucible at different temperature under pure argon atmosphere in an electric resistant furnace. The results indicate that phosphorus distribution ratios increase with an increase of basicity in the slag at the experiment temperature, and then they decrease with an increase of basicity at 1573K and 1623K. The phosphorus distribution ratios decrease with an increase of FetO content in the slag at 1573K, while they increase with an increase of FetO content in the slag and then decrease with an increase of FetO content in the slag at 1623K. The results indicate that the maximum phosphorus distribution ratio between slag and hot metal is 92.4 when basicity of the slag is 1.7 and FetO content in slag is 49.75 mass% at 1623K, and the correspondent phosphorus content in the carbon saturated iron is 0.019mass%. Dephosphorization is easier under low temperature. The equilibrium quotient of phosphorus obtained in the present work is formulated as a function of slag compositions and temperature using the multiple regression method which is used to predict phosphorus content equilibrium with the demanganization slag and optimum conditions needed for ideal phosphorus contents in demanganization pretreatment.

This paper reports on the phase transformation during the preparation of Ni-25Nb, Ni-25Ta, Ni-20Nb-5Ta and Ni-15Nb-10Ta (at-%) powders by high-energy ball milling from elemental powders. The milling process was performed in a planetary ball milling using stainless steel balls and vials, rotary speed of 300rpm, and a ball-to-powder of 10:1. To minimize contamination and spontaneous ignition the powders were handled under argon atmosphere in a glove box. The milled powders were characterized by means of X-ray diffraction techniques. Results indicated that the Ni atoms were preferentially dissolved into the Nb (and/or Ta) lattice at the initial milling times, which contributed to change the relative intensity on the diffraction peaks. After the dissolution of Nb (and/or Ta) into the Ni lattice, the Ni peaks were moved to the direction of lower diffraction angles in Ni-25Nb, Ni-25Ta, Ni-20Nb-5Ta, Ni-15Nb-10Ta powders, indicating that the mechanical alloying was achieved. .

Lithium–oxygen coin cells without catalyst were assembled in argon atmosphere and tested in pure oxygen. Results showed that the first discharge performance of the batteries was strongly affected by the carbon loading, electrolyte amount and current density. At the carbon loading (0.4 mg/cm2), the electrolyte amount (160 μL/cell) and the current density (0.05 mA/cm2), a high capacity of 4586.5 mAh/g was obtained. The capacity decreased when the carbon loading or current density was increased. And the capacity would have a decrease when the amount of electrolyte was decreased. The highest capacity of 6010.2 mAh/g was obtained by optimizing the combination of carbon loading and electrolyte amount at current density of 0.01mA/cm2. However, the discharge capacity sharply decreased from the second cycle. It may be partly due to the fact that the pores of cathode surface were blocked by discharge products at the end of discharge.

A new quaternary amorphous alloy powder Ti50Fe22Ni22Sn6are prepared by mechanical alloying. The milling was performed under an argon atmosphere in a high-energy planetary ball mill. After milled 70h, fully amorphous Ti50Fe22Ni22Sn6powders can be obtained, with the condition of the milling speed, 300rpm, and the weighs ratio of ball to powder, 10:1. Crystal structure of the milled powders is investigated by XRD. Thermal analysis show that when the heating rate increasing from 10K/min to 40K/min, the super-cooled liquid region of milled amorphous alloy increased from 93K to 110K.

12Cr2MoV steel pipe and T91 steel pipe were joined by transient liquid phase diffusion bonding process (TLP) in argon atmosphere using FeNiCrSiB amorphous filler. TP304H steel pipe and 12Cr2MoV steel pipe were joined by the same method using Fe78Si9B13 and BNi2 amorphous filler. The qualified welding joint can be achieved by suitable adjustment of process parameters. The diffusion asymmetry in TLP of different metals has been analyzed. The research shows that there exists a diffusion asymmetry in TLP of different metals. The main reason is the difference of isothermal solidification rate in different materials, which results in a deviation of the bonding interface from the original centerline to T91 and TP304H side.

The pyrolysis characteristics of oil sludge and coal mixed fuel in an argon atmosphere were studied by thermogravimetric analyzer. Factors that affect the pyrolysis process were analyzed. The pyrolysis mechanism equation of the oil sludge and coal fuel was determined. Hereafter, the dynamic properties were provided, namely the activation energy and frequency factor. In this paper, pyrolysis of the mixture occurs in six distinct steps, each accompanied by its unique reactionary mechanics. The activation energy at each step increased with respect to temperature (presenting an initial increase and subsequent decrease). as the rate of temperature increase was amplified, each respective step has its activation energy slightly reduced. Moreover, the mixture shows the influence of non-linear relationships during pyrolysis.

In this research, formation mechanism of a Cu/10 wt.% Cr-10 wt.% Al2O3 nanocomposite via mechanical alloying and subsequent heat treatment has been investigated. It was found that during milling process, Cu (Al) solid solution and Cu9Al4 phase were formed as intermediate products. Further heat treatment carried out under argon atmosphere at 900°C for 8 hours resulted in completion of Cr2O3 reduction by Al. The mechanism of in-situ formation of Al2O3 reinforcement in the copper matrix was also discussed as a two stages process. The SEM and TEM results confirmed the proposed mechanism and showed that the Cr dispersoids surrounded by Al2O3, in the nanometric scale. Also, the Cu matrix with mean crystallite size of 30 nm was stable at high temperature.

Under the protected condition of the purified argon atmosphere, Mo-ZrO2cermets were sintered by Mo powder and ZrO2powder at 1873K for 2 hours. Mircostructure of cermets were observed by means of XRD, optical microscope and SEM anslysis. Electrical properties of sintered samples with different Mo content and temperature were measured using DC four-electrode method. The results showed that metal phase and ceramic phase were independent of each other. With the reduction of Mo content, Mo metal phase as the continuous network structure is dispersedly distributed in the ceramic phase zone. The electrical conductivity of cermets at room temperature increased with decreaseing of the Mo content. The trend that the high-temperature electrical conductivity of cermets changed with the Mo content is the same as the trend that at the room temperature. When the Mo content is greater than 40%, the high-temperature electrical conductivity increased linearly with increasing temperature. The electrical conductivity of 40mol-% Mo-ZrO2reached the peak at 1223K and 1473K.

The high performance diamond brazed saw was developed to cut efficiently AZ31 Magnesium Alloy. The Ti-coated diamond and the uncoated diamond were brazed with NiCr alloy by high-frequency induction under argon atmosphere at 1040°C within 20 seconds. Scanning electron microscopy (SEM), energy dispersion spectrometer (EDS) and X-ray diffraction (XRD) were used to investigate the interfacial microstructures between brazed diamond and the filler alloy. The results show that Cr-carbides forms normally and compactly on the surface of Ti-coated diamond brazed, whereas Cr-carbide forms tangentially and loosely on the surface of uncoated diamond brazed. That is because Ti has changed the mechanism of Cr-carbides formed on the surface of diamond brazed. The test of cutting AZ31 magnesium alloy plate shows that the section cut by Ti-coated diamond saw is much smoother than that cut by uncoated diamond saw after a long time.

The wettability between pure liquid titanium and calcia-stabilized zirconia was studied in argon atmosphere. The micrographic observations made on cross section perpendicular to the interface using SEM showed that interfacial reaction occurred. However, the contact angles were larger than 90°within experimental duration.

Impact of heat treatment on hot isostatically pressed (HIP) Ni-base superalloy has been investigated before and after conducting HIP process. HIP was performed by applying a stress of 120 MPa at a temperature of 1200 °C for 2 hours under argon atmosphere followed by furnace cooling to room temperature. Heat treatment cycle was conducted on the samples according to GEB50A563. Microstructural observation demonstrated the deleterious change of  morphology after HIP process which causes to decrease of hardness and creep strength. However, pre heat treatment in compared with cast specimen show slight changes in microstructure but, post heat treatment can revert this change of  morphology completely and also increase the mechanical properties.

Mg-9Li-3Al-xSr alloys were prepared in vacuum furnace under the protection of argon atmosphere. Effects of Sr content on microstructure and mechanical properties of as-cast Mg-9Li-3Al alloys were investigated. The results indicate that α-Mg and β-Li phases exist in all alloys. The addition of Sr causes grain refinement of the test alloys and new Al4Sr phase is formed in the alloys. The mechanical properties of alloys initially increase and then decrease with the increase of Sr content. Sr has obvious refining effect on the alloys and the distribution of Al4Sr phase is much more uniformly when Sr content is 2.5wt%,. The as-cast Mg-9Li-3Al-2.5Sr alloy exhibits an optimum combination of mechanical properties with the ultimate strength, yield strength and elongation of 186MPa, 149MPa and 11% respectively, improving obviously compared with Mg-9Li-3Al alloy. With the continuing increase of Sr content, the mechanical properties of the test alloys decrease.

The Ir-Al powder in the 1:1 atomic ratio was obtained by high energy mechanical alloying in a Pulverisette 4 Fritch planetary mill. The final product was obtained after 28 h of milling in argon atmosphere. Alloy formation was investigated by X-ray diffraction. After 4 h of milling the new structure of IrAl compound is found in the diffraction patterns. The obtained powders are nanocrystalline with a mean crystallite size of 11 nm after 28 h of milling. The particle morphology and the chemical homogeneity were studied using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDX). It was found that the obtained compound present large particles composed by smaller one.

It has been demonstrated that V6O13 is a very attractive cathode materials for rechargeable lithium-ion batteries. Cr3+ was doped to improve its electrochemical property. CrxV6O13(x =0.01~0.05) cathode materials were prepared using NH4VO3 and Cr2O3 as raw material by solid phase method in argon atmosphere. The best electrochemical properties of CrxV6O13 were obtained under the optimum conditions as follows: the argon flow rate is 85mL/min, the heating rate is 5°C /min, the holding time 1h at 180°C, 1h at 300°C and 30 min at 450°C. The structural and electrochemical properties were examined by means of X-ray diffraction, SEM and charge–discharge tests. The results demonstrated that the powders maintain double cavity chain structure regardless of the chromium doping. When the Cr doping of x = 0.03, capacity is highest. Maximum initial discharge capacity is 334mA•h/g, 80% of theoretical capacity. During discharge process there is 6.5 Li+ embedded in the Molecules of doping. After discharge cathode became Li6.5Cr0.03V6O13.

In this paper we will try to further clarify the creep-strength degradation of selected advanced creep resistant steels. In order to accelerate some microstructural changes and thus to simulate degradation processes in long-term service, isothermal ageing at 650°C for 10000 h was applied to P91, P92 and P23 steels in their as-received states. The accelerated tensile creep tests were performed at temperature 600°C in argon atmosphere on all steels in the as-received state and after long-term isothermal ageing, in an effort to obtain a more complete description of the role of microstructural stability in high temperature creep of these steels. Creep tests were followed by microstructural investigations by means of both transmission and scanning electron microscopy and by the thermodynamic calculations. It is suggested that microstructural instability is the main detrimental process in the long-term degradation of the creep rupture strength of these steels.

Highly pure and dense bulk Ti2AlC was prepared by hot-pressing a mixture of the “312” phase Ti3AlC2 powders, and the element Ti and Al powders. Different ratios of the starting materials and different sintering temperature were attempted in order to obtain a highly pure and dense bulk Ti2AlC sample. Phase analysis and microstructures observing were performed by using by XRD, SEM as well as an X-ray fluorescence spectrometer. The results show that a nearly full dense bulk Ti2AlC sample can be prepared at 1300°C and 30MPa for 30 minutes in argon atmosphere. A dominant mechanism to form the “211” phase Ti2AlC can be attributed to the directly connecting between Al and Ti6C octahedron, which is as an intermediate phase in the Al-rich liquid mediator during the hot pressing.

ZrB2-SiC and ZrB2-SiC-C ultra-high temperature ceramics (UHTCs) were fabricated by pressureless sintering under an argon atmosphere. The mass and linear ablation rates were tested in an oxyacetylene flame with high velocity. The microstructure and phase transformation of the ZrB2-based UHTCs were characterized by scanning electron microscopy along with energy dispersive spectrometry. Results show that the UHTCs have excellent properties of ablation resistance at ultra-high temperature. The values of mass and linear ablation rates were lower in the ZrB2-SiC UHTCs than those measured for ZrB2-SiC-C. The effect of C addition on the ablation resistant was not obvious but it influenced the microstructure of the ZrB2-SiC UHTCs. And the ablation resistant mechanisms of ZrB2-based UHTCs were discussed according to microstructure analysis.

We investigate by means of Atomic Force Microscopy and Scanning Electron Microscopy the surface modifications of 3C-SiC(111)/Si epilayers induced by thermal annealing performed under hydrogen or argon atmosphere. We explore the effects of these treatments both on as grown and polished epilayers. Owing to an important initial surface roughness, the annealing has few impact on as grown films. On polished epilayers, a surface reorganization via the formation of a regular array of steps is evidenced. The proper effect of each gas on the surface reorganization is discussed.

The goal of our studies is to find alloy compositions capable of high H capacity and reversible low temperature hydrogenation. In the present research work, specimens with nominal compositions Zr0.9Ti0.1Cr1.2V0.8 and Zr0.9Ti0.1Cr0.8V0.8Ni0.4 have been prepared by arc–melting under argon atmosphere. The microstructural properties of the samples were analyzed by XRD and SEM, while the corresponding microchemistry was determined by EDAX measurements. A two phase system was regularly obtained, with the main component being the hexagonal (C14) Laves phase. The presence of small amounts of Ni has been found to increase the alloy activity on hydrogen. Hydrogen activation was performed for both samples and charging-discharging properties were investigated in the temperature range between 20 oC and 100 oC by using a Sievert-type apparatus.

The high-powered brazing diamond saw was developed to cut vehicle tyre efficiently. The Ti-coated diamond and the uncoated diamond were brazed with NiCr alloy by high-frequency induction under argon atmosphere at 1020°C within 10 seconds. The interfacial microstructures between brazed diamond and the filler alloy were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersion spectrometer (EDS). It is surprisedly found that Cr-carbides forms compactly and normally on the surface of Ti-coated diamond brazed, whereas Cr-carbide forms loosely and tangentially on the surface of uncoated diamond brazed. The abrade experiment results for the brazed diamonds show that the bond strength between the Cr-carbide and uncoated diamond brazed is lower than the normally formed Cr-carbide and the diamond. Furthermore, the cause that Ti changes the morphology of Cr-carbides on the surface of Ti-coated diamond brazed is discussed by the further tests that are specially designed.

In the present work, biomorphic TiC/C ceramic with a woodlike structure was synthesized from wood template. The TiC coatings were formed on the surface of C-wood-template in a reaction medium consisting of Ti powder in a mixture of molten LiCl-KCl salts under an argon atmosphere. The structure and biomorph of the TiC/C ceramic were characterized by XRD, TG-DSC, SEM and EDX analyses. The results indicated that Ti powder had reacted with carbon in the cellular wall to form TiC coatings. The resulting biomorphic TiC/C ceramic retained well the structure of the original biomorph of the wood.

The surface modification of SiC powder with an alumina precursor was achieved by a sol-gel method to apply the electrophoretic deposition (EPD) technique to the shaping of the SiC powder. The isoelectric point of the surface-modified SiC powder with sol-gel-derived alumina precursor was shifted to around pH 9, which is close to that of alumina. The alumina-coated SiC deposited on a cathodic substrate by EPD. The green compact of surface-modified SiC powder was sintered by hot pressing in an argon atmosphere at 2000oC.

Solid-state direct diffusion bonding between commercially pure nickel and tungsten carbide (with 6%Cobalt) has been carried out in the temperature of 980°C and 1100°C using different holding times in argon atmosphere. Samples were successfully joined without defects or cracks on the joining interface with the exception of the one joined at 980°C for 5 min. The results showed that joining occurred by the formation of a reaction zone. Scanning electron micrographs show that different intermediate layers are formed in the reaction zone, and the width of these layers increases with an increase in bonding temperature and time. Electron probe microanalysis revealed that at any particular bonding temperature, cobalt travel into the nickel side, whereas nickel travel comparatively larger distances in the tungsten carbide side.

Powders of elemental Mg, Zn, Al and Ag were milled in order to produce nanocrystalline alloys with nominal composition Mg98M2 (M=Zn, Al and Ag). Pure Mg was also mechanically milled without any additions. Single-phase nanocrystalline (crystal size 24-26 nm) Mg98M2 alloys were produced after 216 ks of milling. A passivity procedure was followed immediately after milling, by gradually exposing the alloy powders to air (~ 12 hrs). After this procedure, the mechanically alloyed powders were kept under argon atmosphere before being hydrided at 200 and 300 °C under 0.5 and 3 MPa P for 10 min. Previously milled (~ 1.5 years before) and passivated powder alloys (stored in air and referred to as “AE” samples) were also hydrided under the same conditions. No hydriding was observed in the as-received Mg powders (crystal size >> 100 nm), but the as-milled, passivated nanocrystalline alloys were partially hydrided (even the AE samples). The amounts of the MgH2 phase in the hydrided samples were larger in the Ar-stored than in the AE samples under all hydriding conditions. The possible role of MgO and Mg hydroxides, as well as of the alloying elements, on the hydriding behavior of the nanostructured, mechanically alloyed powder alloys is discussed.

In this study, weldability of bronze parts produced by powder metallurgy has been investigated by using TIG welding technique. Bronze powders were pressed into 55x44x5 mm size specimens under pressure of 350 MPa. Then these specimens were sintered at 650, 750 and 870 °C for 45 minute under argon atmosphere. Finally, the parts were welded by TIG welding method. Hardness values of the welded joints were measured and microstructural features were investigated.