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International audience; In this work, the structural evolution of Al-16 at.%Fe-2 at.%TM (Transition Metals (TM): Ti, Ni, Cu) alloys during mechanical alloying and their magnetic properties were investigated. The evolution of the phase composition and microstructure of the alloys with the milling time was studied using X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The phase composition of the alloys was determined using the Rietveld refinement of the XRD profiles. It was shown that the interaction between the components of the powder mixtures during milling started with dissolution of Fe in the Al crystalline lattice and Al in the Fe crystalline lattice. Upon further milling, ferromagnetic AIFe(3) (DO3) formed and further transformed into paramagnetic bcc-AIFe and later into an amorphous phase. It was found that the TM alloying elements significantly influence the kinetics of the transformations during milling: the Al82Fe16Ni2 alloy was fully amorphous after 40 h of milling, the Al82Fe16Ni2 alloy required 50 h of milling to achieve complete amorphization, and the Al82Fe16Ni2 alloy was only partially amorphous after 60 h of milling. The interpretation of the observed alloying effect has been proposed. The magnetic properties of the alloys were correlated with the results of the structural characterization.

The in situ formation of TiB2particulates via an interface reaction between Ti and FeB powders was studied. The effects of mechanical activation by high-energy milling on the decomposition of TiH2and the interface reactions between Ti and FeB powders to form TiB2were investigated. Powder mixtures were fabricated using planetary ball-milling under various milling conditions. The specific ball-milling energy was calculated from the measured electrical power consumption during milling process. High specific milling energy (152.6 kJ/g) resulted in a size reduction and homogeneous dispersion of constituent powders. This resulted in a decrease in the decomposition temperature of TiH2and an increase in the formation reaction of TiB2particulates in the Fe matrix, resulting in a homogeneous microstructure of nanoscale TiB2evenly distributed within the Fe matrix. In contrast, the powder mixture milled with low specific milling energy (36.5 kJ/g) showed an inhomogeneous microstructure composed of relatively large Fe-Fe2B particles surrounded by a thin layer of Fe-TiB2within a finely dispersed Fe-TiB2matrix region.

Despite the prescribed benefits of insulin widely used in treating diabetes, patients still feel the inconvenience and perceived pain related to multiple daily administrations by needle insulin injections. Approved inhaled insulin of the second generation has not so far achieved expectations. Design of needle-free delivery systems for insulin is an active area of research and this paper reports on the development of a new needle-free approach to deliver insulin treating diabetes. Porous TiNi-based alloys serve as high-density materials being capable of holding insulin solutions within the structure of the material, and infrared radiation promotes the directional diffusion of insulin from the TiNi porous structure into the skin. Taking these two facts into account, the needle-free device (NFD) for delivering insulin uses a new porous-permeable TiNi-based material and a novel infrared radiation mediated delivery system. The NFD described causes no skin irritation or lesions and is safe to use in practice. Its efficiency in delivering insulin was clinically assessed on 42 diabetic patients. The results show promising prospects as a new technology for delivering insulin and other liquid drugs. Copyright © 2016 VBRI Press.

The present work addresses the structural-phase state changes of porous TiNi-based compounds fabricated by reaction sintering (RS) of Ti and Ni powders with Co, Mo, and no additives introduced. The study also emphasizes the features of a reaction cell (RC) during the transition from the solid- to liquid-phase sintering. Mechanisms of phase transformations occurring in the solid phase, involving the low-melting Ti2Ni phase within the RC, have been highlighted. Also, the intermediate Ti2Ni phase had a crucial role to provide both the required RS behavior and modified phase composition of RS samples, and besides, it is found to be responsible for the near-equiatomic TiNi saturation of the melt. Both cobalt and molybdenum additives are shown to cause additional structuring of the transition zone (TZ) at the Ti2Ni−TiNi interface and broadening of this zone. The impact of Co and Mo on the Ti2Ni phase is evident through fissuring of this phase layer, which is referred to solidified stresses increased in the layer due to post-alloying defects in the structure.

Two sintering methods of a pressureless sintering and a spark-plasma sintering are tested to densify the Fe-TiC composite powders which are fabricated by high-energy ball-milling. A powder mixture of Fe and TiC is prepared in a planetary ball mill at a rotation speed of 500 rpm for 1h. Pressureless sintering is performed at 1100, 1200 and for 1-3 hours in a tube furnace under flowing argon gas atmosphere. Spark-plasma sintering is carried out under the following condition: sintering temperature of , soaking time of 10 min, sintering pressure of 50 MPa, heating rate of , and in a vacuum of 0.1 Pa. The curves of shrinkage and its derivative (shrinkage rate) are obtained from the data stored automatically during sintering process. The densification behaviors are investigated from the observation of fracture surface and cross-section of the sintered compacts. The pressureless-sintered powder compacts show incomplete densification with a relative denstiy of 86.1% after sintering at for 3h. Spark-plasma sintering at for 10 min exhibits nearly complete densification of 98.6% relative density under the sintering pressure of 50 MPa.

Objectives : Repetitive and stereotyped behaviors are core symptoms in children with autism spectrum disorders (ASD). The purpose of our study was to investigate the frequency of motor stereotypes in ASD children and their clinical features. Methods : Among 171 ASD children (age range, 3-15), the ASD group with motor stereotypes was defined according to two items in the Korean version of Autism Diagnostic Interview-Revised (K-ADI-R). We compared the clinical features, behavior problems and severity of other domains in the K-ADI-R and executive functions between the ASD group with motor stereotypes and the ASD group without motor stereotypes. Results : Ninety (52.6%) of 171 ASD children had motor stereotypes. The ASD group with motor stereotypes had a lower intelligence quotient score (62.23 vs. 84.94, p

Thermoelastic martensitic transformations play a fundamental role in the shape memory effect and related phenomena. Owing to their unique crystallographic and thermomechanical behaviour, martensitic transformations have generated considerable research in the areas of crystallography, thermodynamics and mechanical behaviour. In the area of thermodynamics a theoretical approach is now added which provides the basis for thermoelastic behaviour through consideration of the Gibbs energy change. In this paper, the interrelation of internal elastic stresses and martensite shear stresses in phase transitions has been defined. A thermoelastic stress equilibrium equation for a wide range of martensitic transformation temperatures has been presented. On the basis of the calculations made, an estimation of dislocation defects formation energy for the TiNi-based alloy has been made. For TiNi-based composition made of TN-10 brand alloy, commercially produced for medical goals, the energy of vacancy formation is about 0.06 kcal/mol. The study and calculations are shown to make clear, using a new approach, the considering of phase transitions in terms of external and internal stresses. Copyright © 2015 VBRI Press.

The brief overview of published articles on Nitinol studies reflects, in fact, a little misunderstanding of a thermodynamic importance since there is no whole concept or paradigm considering the martensite transition and related effects in terms of thermodynamic arguments. TiNi-based alloys are basically functional materials. They're more important for what they do than for what they are. In order to make it easier to understand complicated behavior of TiNi-based alloys under general and special conditions, a new approach is introduced. This work was aimed at studying the hysteretic behavior of TiNi-based alloys. Mechanism of hysteretic phenomenon in TiNi-based alloys showing shape memory effect, superelasticity and ferroelasticity has been considered. Hysteretic behavior in repeatable shape memory effect was thermodynamically analyzed with the aid of Helmholtz potential formalism. Correlation of deformation, temperature and latent heat of phase transition under the constant load was established. Maximum hysteresis width achieves when the product  during phase transition tends to H, and when the product  tends to zero the value of T approximates the difference (As - Mf) or (Af - Ms). Copyright © 2014 VBRI press.

Al-Fe-Y amorphous alloys of Al84Fe16, Al82Fe18 and Al82Fe16Y2 composition were prepared by mechanical alloying in a planetary ball mill P100. A nearly complete amorphization could be achieved for the Al84Fe16, Al82Fe18 and Al82Fe16Y2 powder alloys after 100h of milling at a rotational speed of 350 rpm in hexane medium. Differential scanning calorimetry (DSC) analyses revealed three-stage crystallization processes for Al82Fe18 and Al82Fe16Y2 alloys and four-stage crystallization processes for Al84Fe16 alloy, respectively. Taking into account the DSC data, the thermal stability increased in the order of Al84Fe16, Al82Fe18, and Al82Fe16Y2 composition. The Al82Fe16Y2 alloy exhibited a relatively better thermal stability than the other two alloys.

Conducting polymer composites have many interesting physical properties and important application potentials. Suitable combinations of metal nanoparticles with conductive polymers can result in composite materials having unique physical and chemical properties that can have wide application potential in diverse areas. In this work, copper nanoparticles were fabricated by electrical explosion of wire (EEW) in solution of polyacrylic acid (PAA) and ethanol. Conductive polyaniline-copper (PANI-Cu) composites have been synthesized by in-situ polymerization of aniline in the fabricated copper suspension. Optical absorption in the UV-visible region of these suspensions was measured in the range of 200-900 nm. Morphology and structure of the composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectra (FTIR). Pure copper nanoparticles were uniformly dispersed into the polymer matrix. Thermal stability of the composites was characterized by thermogravimetric analysis (TGA). Electrical conductivity measurements indicated that the conductivity of the composites was higher than that of pure polyaniline and increased with increasing content of copper.

Fe-TiC composite was fabricated from Fe and TiC powders by high-energy milling and subsequent spark-plasma sintering. The microstructure, particle size and phase of Fe-TiC composite powders were investigated by field emission scanning electron microscopy and X-ray diffraction to evaluate the effect of milling conditions on the size and distribution of TiC particles in Fe matrix. TiC particle size decreased with milling time. The average TiC particle size of 38 nm was obtained after 60 minutes of milling at 1000 rpm. Prepared Fe-TiC powder mixture was densified by spark-plasma sintering. Sintered Fe-TiC compacts showed a relative density of 91.7~96.2%. The average TiC particle size of 150 nm was observed from the FE-SEM image. The microstructure, densification behavior, Vickers hardness, and fracture toughness of Fe-TiC sintered compact were investigated.

In this work, the effect of a slight change in the composition of the Al-Fe amorphous alloys (from Al84Fe16to Al82Fe18) and the substitution of Y for Al (2 at.%) on their crystallization kinetics was studied. According to the X-ray diffraction analysis, powders of the Al84Fe16, Al82Fe18, and Al82Fe16Y2alloys with a fully amorphous structure were formed after 100 h of mechanical milling of the mixtures of the elemental powders. The crystallization behavior of the alloys was also studied by transmission electron microscopy. Upon heating up to a temperature of the first exothermic peak,α-Al crystals precipitated from the amorphous Al84Fe16matrix. During crystallization of the Al82Fe18alloy, crystals of the Al6Fe intermetallic compound formed along withα-Al crystals. Substitution of Y for 2 at.% of Al in the Al82Fe16Y2alloy made crystallization of the alloy more complicated:α-Al, Al6Fe, and Fe4Y crystals coexisted with an amorphous phase. The activation energies corresponding to the first crystallization event of the alloys were calculated using the Kissinger and Ozawa methods. The values obtained by these two methods were in good agreement with each other and the same trends of changing with the alloy composition were observed. The Avrami exponentnwas determined from the Johnson-Mehl-Avrami equation and showed that crystallization at the first stage is interface-controlled growth for all the three powder alloys studied.

The consolidation results of fine tungsten powders, W-Cu composite and W/Cu FGM by using a novel method combining resistance sintering with ultra high pressure have been reviewed. The densification effects of the consolidation parameters, including pressure, input power and sintering time, have been investigated. The sintering mechanism of this method was quite different from other sintering methods. Particle rearrangement, sliding, distortion and crushing due to the ultra high pressure are the dominant mehanisms at the initial stage, then the dominant sintering mechanisms are transient arc-fused processes controlled by the input power.

：A significant proportion of children with autism spectrum disorders (ASD) have regression characterized by loss of previously acquired skills. The purpose of this study was to compare demographic, clinical characteristics and autism-related symptomatology of the children who have regression with children who don’t have regression.

The Cu nanofluid in ethylene glycol was prepared by electrical explosion of wire, a novel one-step method. The X-ray diffraction, field emission scanning electron microscope and transmission electron microscope were used to study the properties of Cu nanoparticles. The results showed that the nanoparticles were consisted of pure face-centered cubic structure and near spherical shape with average grain size of 65 nm. Ultraviolet-visible spectroscopy (UV-Vis) confirmed Cu nanoparticles with a single absorbance peak of Cu surface plasmon resonance band at 600 nm. The nanofluid was found to be stable due to high positive zeta potential value, +51 mV. The backscattering level of nanofluid in static stationary was decreased about 2% for 5 days. The thermal conductivity measurement showed that Cu-ethylene glycol nanofluid with low concentration of nanoparticles had higher thermal conductivity than based fluid. The enhancement of thermal conductivity of nanofluid at a volume fraction of 0.1% was approximately 5.2%.

The present work studied the synthesis of Fe–Ni Invar alloy nanopowder by the electrical explosion of wire (EEW) in deionized water. X-ray diffraction (XRD) was used to investigate the phase of the nanopowder. It indicated that the as-synthesized nanopowder had γ-Fe–Ni solid solution and FeO phase. Pure γ-Fe–Ni phase was obtained when the as-synthesized powder was reduced under the hydrogen at 700 °C for 30 min. Particle sizes of the as-synthesized and the reduced powders were observed by electron transmission microscope. The as-synthesized and the reduced nanopowders were in a nearly spherical shape with average size of 32.5 and 180 nm, respectively. The as-synthesized particles had a core–shell structure that was composed of γ-Fe–Ni in the core and FeO in the shell. The alloy compositions of the wire before exploding and the reduced nanopowder determined by electron probe microanalysis were almost the same. The hysteresis loop of the as-synthesized nanopowder, the hydrogen-reduced nanopowder and the sintered sample were examined with a vibrating sample magnetometer. The sintered sample had the smallest coercivity with a value of 14.26 Oe.

In this work, effect of various process-control agents (PCAs) on the mechanical alloying of amorphous alloy of Al 85 Y 8 Ni 5 Co 2 has been investigated. The dependence of the particle shape, size and crystallization behavior of the amorphous alloy powders on the type of PCAs and their concentrations was investigated by using X-ray diffraction, field-emission scanning electron microscopy and differential scanning calorimetry. It was found that the additive of toluene could affect positively the amorphization and thermally induced crystallization processes, as well as the size refinement, morphology and particle-size distribution of as-milled powders in comparison with alloy obtained without PCA.

We produced cylindrical porous TiNi bodies by Self-propagating High-temperature Synthesis (SHS) process, varying the heating schedule prior to ignition of a loose preform compact made from (Ti+Ni) powder mixture. To investigate the effect of the heating schedule on the behaviour of combustion wave propagation and the structure of porous TiNi shape-memory alloy (SMA) body, change of temperature in the compact during SHS process was measured as a function of time and used for determining combustion temperature and combustion wave velocity. Microstructure of produced porous TiNi SMA body was observed and the results were discussed with the combustion characteristics. From the results it was concluded that the final average pore size could be controlled either by the combustion wave velocity or by the average temperature of the preform compact prior to ignition.

The present study deals with structural transformations induced by high-energy ball-milling of an amorphous Fe90Zr10 alloy prepared by melt-spinning. The amorphous melt-spun ribbons were found to undergo crystallization into BCC alpha-Fe(Zr) nanocrystallites under high-energy ball milling. The decomposition degree of the amorphous phase increased with increasing milling time and intensity. Our results suggest that the observed crystallization is a deformation-induced process rather than a thermally induced one.

Fe based (FeCSiBPCrMoAl) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The Fe-based amorphous powders and the Fe-Cu composite powders were compacted by a spark plasma sintering (SPS) process. Densification of the Fe amorphous-Cu composited powders by spark plasma sintering of was occurred through a plastic deformation of the each amorphous powder and Cu phase. The SPS samples milled by AGO-2 under 500 rpm had the best homogeneity of Cu phase and showed the smallest Cu pool size. Micro-Vickers hardness of the as-SPSed specimens was changed with the milling processes.

TiCuNiAl quaternary amorphous alloy was prepared by high-energy ball milling process. A complete amorphization was confirmed for the composition of TiCuNiAl after milling for 30hrs. Differential scanning calorimetry showed a large super-cooled liquid region (T

SolcoNanoadvance Inc. Doodea-dong, Changwon, 641-771, Korea(Received April 9, 2009; Revised April 28, 2009; Accepted May 8, 2009)Abstract This paper presents a novel single-step method to prepare the Ag nanometallic particle dispersedfluid (nanofluid) by electrical explosion of wire in liquid, deionized water (DI water). X-ray diffraction (XRD),field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) were usedvestigate the charact in to openl w ms also utia- a tor t asude dispeeo pnsiore th pstar ee Z . s idueristics the Agl f f oona nerties of the as-prepared Ag nanofluid. Pure Ag phase was detected in the nanofluids using water. FE-SEM anal-ysis shows that the size of the particles formed in DI water was about 88 nm and Zeta potential value was about -43.68 without any physical and chemical treatments. Thermal conductivity of the as-prepared Ag particle dis-persed nanofluid shows much higher value than that of pure DI water. Keywords : Nanofluid, Dispersion property, Electrical explosion of wire

Tix(CuNi)90–xAl10 (x = 50, 55, 60) amorphous powder alloys were synthesized by mechanical alloying technique. The evolution of amorphization during milling and subsequent heat treatment was investigated by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and transmission electron microscopy. The fully amorphous powders were obtained in the Ti50Cu20Ni20Al10, Ti55Cu17.5Ni17.5Al10 and Ti60Cu15Ni15Al10 alloys after milling for 30, 20 and 15 h, respectively. Differential scanning calorimetry revealed that thermal stability increased with the increasing (CuNi) content: Ti60Cu15Ni15Al10, Ti55Cu17.5Ni17.5Al10 and Ti50Cu20Ni20Al10. Heating of the three amorphous alloys at 800 K for 10 min results in the formation of the NiTi, NiTi2 and CuTi2 intermetallic phases.

Amorphization and crystallization behaviors of powders during high-energy ball milling and subsequent heat treatment were studied. Full amorphization obtained after milling for 30 h was confirmed by X-ray diffraction and transmission electron microscope. The morphology of powders prepared using different milling times was observed by field-emission scanning electron microscope. The powders developed a fine, layered, homogeneous structure with prolonged milling. The crystallization behavior showed that the glass transition, , onset crystallization, , and super cooled liquid range ${\Delta}T

Al-based metal matrix composites were synthesized through powder metallurgy methods by hot extrusion of elemental Al powder blended with different amounts of metallic glass reinforcements. The glass reinforcement was produced by controlled milling of melt-spun Al85Y8Ni5Co2 glassy ribbons. The composite powders were consolidated into highly dense bulk specimens at temperatures within the supercooled liquid region. The mechanical properties of pure Al are improved by the addition of the glass reinforcements. The maximum stress increases from 155 MPa for pure Al to 255 and 295 MPa for the samples with 30 and 50 vol.% of glassy phase, respectively. The composites display appreciable ductility with a strain at maximum stress ranging between 7% and 10%. The mechanical properties of the glass-reinforced composites can be modeled by using the iso-stress Reuss model, which allows the prediction of the mechanical properties of a composite from the volume-weighted averages of the components properties.

Focused ion-beam milling has been applied to prepare needle-shaped atom probe tomography specimens from mechanically alloyed powders without the use of embedding media. The lift-out technique known from transmission electron microscopy specimen preparation was modified to cut micron-sized square cross-sectional blanks out of single powder particles. A sequence of rectangular cuts and annular milling showed the highest efficiency for sharpening the blanks to tips. First atom probe results on a Fe95Cu5powder mechanically alloyed in a high-energy planetary ball mill for 20 h have been obtained. Concentration profiles taken from this powder sample showed that the Cu distribution is inhomogeneous on a nanoscale and that the mechanical alloying process has not been completed yet. In addition, small clusters of oxygen, stemming from the ball milling process, have been detected. Annular milling with 30 keV Ga ions and beam currents ≥50 pA was found to cause the formation of an amorphous surface layer, whereas no structural changes could be observed for beam currents ≤10 pA.

A bulk metallic glass of Ti 50 Cu 25 Ni 20 Sn 5 nominal composition was produced via a powder metallurgical route, namely the preparation of glassy powders by mechanical alloying followed by their consolidation by spark-plasma sintering. Samples were characterized with respect to their structure and thermal properties before and after sintering. A bulk glassy sample, having nearly full density and containing only a small fraction of the intermetallic NiTi 2 phase, could be obtained after careful selection of sintering parameters.

High-energy ball-milling in hexane medium was employed to prepare amorphous Al-La-Fe-Ni alloys of three different nominal compositions (Al 82 La 10 Ni 4 Fe 4 , Al 85 La 9 Ni 3 Fe 3 and Al 88 La 6 Ni 3 Fe 3 , numbers indicate at.%). Using a planetary ball-mill (AGO-2) at a rotational speed of 300 rpm, nearly complete amorphization could be achieved for the Al 82 La 10 Ni 4 Fe 4 alloy after milling for 350 h. In contrast, the Al 85 La 9 Ni 3 Fe 3 and Al 88 La 6 Ni 3 Fe 3 samples remained crystalline to a certain extent even after prolonged milling and contained FCC Al crystallites. The glass forming ability was found to increase with decreasing Al and increasing La content, which can be ascribed to the enhanced atomic size mismatch of the constituents on La addition. Amorphous Al 82 La 10 Ni 4 Fe 4 powder undergoes two-stage crystallization with onset temperatures at 640 and 700 K and glass transition at 566 K. Differences to DSC traces of previously studied melt-spun samples are believed to be mainly due to carbon impurity incorporation and compositional changes during milling. Taking into account the DSC data, consolidation of amorphous Al 82 La 10 Ni 4 Fe 4 powder was attempted by means of spark-plasma sintering at a temperature of 613 K and applied pressures of 400 and 600 MPa. Compacts produced under these conditions were found to have relative densities of 80% and 96%, respectively.

The decomposition behavior of FeSn, CoSn and CoIn2 intermetallics under high-energy ball-milling has been investigated using X-ray diffraction, calorimetric and magnetization measurements. Upon milling a large amount of the FeSn intermetallic decomposes into Fe5Sn3 and FeSn2, where the average grain size of the product phases stays nearly constant with milling-time. Similar observations are made for the CoSn intermetallic, which decomposes into Co3Sn2 and Sn. It is suggested that the mechanically driven decomposition of FeSn and CoSn results from local melting of powder particles due to high temperature pulses during ball collisions. In contrast to FeSn and CoSn, CoIn2 does not undergo decomposition upon milling. The different decomposition behaviors of the studied intermetallics may be attributed to the volume changes occurring with a decomposition process. Whereas a negative volume change is associated with the decomposition of FeSn and CoSn into their product phases, the decomposition of CoIn2 leads to an increase in volume. Hence, high local stresses under ball collisions are expected to make the mechanically induced decomposition of FeSn and CoSn favorable but rather hinder the decomposition of CoIn2.

The structural evolution of an amorphous Fe 90 Zr 10 alloy under high-energy mechanical deformations was investigated by means of X-ray diffraction, Moessbauer spectroscopy and magnetic measurements. Ball milling of melt-spun Fe 90 Zr 10 ribbons in a planetary ball mill (AGO-2) induces their crystallization into supersaturated α-Fe(Zr) grains. The crystallization degree of the amorphous phase increases with increasing milling time, with a fully crystalline state being obtained after 30 min at a milling speed of 1000 rpm. The Zr content of the Fe grains reaches a maximum of about 3 at.% after milling for 30 min. Moessbauer spectra and saturation magnetization measurements suggest that the remaining Zr atoms are most likely segregated at the grain boundaries. Analyses of samples milled at different speeds reveal that the crystallization seems to be a deformation-induced process rather than a thermally induced one.

TiB2-43vol.%Cu nanocomposite powders with titanium diboride particle size 50-100 nm were cold and detonation sprayed in order to fabricate coatings on a copper substrate. The powders were produced by self-propagating high-temperature synthesis (SHS) followed by mechanical milling. The temperatures during spraying were calculated and the change in the nanostructure of the powders during spraying was studied: in cold sprayed coatings the size of TiB2 particles was well retained, in detonation sprayed coatings the growth of the particles was observed, the mode of spraying greatly affecting the microstructure and the size of the particles. The hardness of cold sprayed coatings was higher compared to detonation sprayed coatings. This research shows the future potential for development of coatings with submicron and nanostructure by cold and detonation spraying of powders produced by mechanical milling.

TiB2-Cu composites in a nanostructured state are candidates for high-strength conductive and erosion-resistant materials. In this work, we studied formation of nanostructured TiB2-Cu composites under shock wave conditions. We investigated the influence of preliminary mechanical activation (MA) of Ti-B-Cu powder mixtures on the peculiarities of the reaction between Ti and B under shock wave. In the MA-ed mixture the reaction proceeded completely while in the nonactivated mixture the reagents remained along with the product – titanium diboride. The size of titanium diboride particles in the central part of the compact was 100-300 nm. This research shows that shock wave synthesis in mechanically activated powder mixtures with simultaneous compaction of the composite is a promising way to materials with submicron and nanostructures.

In the present work, Cu-TiB2 nanocomposite powders were synthesized by combining high-energy ball-milling of Cu-Ti-B mixtures and subsequent self-propagating high temperature synthesis (SHS). Cu-40wt.%TiB2 powders were produced by SHS reaction and ball-milled. The milled SHS powder was mixed with Cu powders by ball milling to produce Cu-2.5wt.%TiB2 composites. TiB2 particles less than 250nm were formed in the copper matrix after SHS-reaction. The releative density, electrical conductivity and hardness of specimens sintered at 650-750°C were nearly 98%, 83%IACS and 71HRB, respectively. After heat treatment at 850 to 950°C for 2 hours under Ar atmosphere, hardness was descedned by 15%. Our Cu-TiB2 composite showed good thermal stability at eleveated temperature.