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After the crucibles were cooled to ambient temperature, the samples were taken out of the crucibles and the oxide slag at the top of the sample was removed by grinding, finally, the ceramic discs of 150 mm in diameter and 20 mm in thickness were obtained.
According to the literature [4, 5], in order to increase the reactivity of the green powders, the process has been taken to combine simultaneously or successively ball milling (MA) and an SHS reaction since 1990s, and can be currently classified two routes, one is mechanically-induced self-propagating reactions (MRS) for which as SHS reaction occurs during milling inside the ball mill after same activation time, when the powder reaches a well-defined critical state, whereas the other is mechanically activated self-propagating high-temperature synthesis (MASHS) which consists of a short duration high-energy ball milling step followed by SHS.
As a result, combustion velocity sharply increased in the presence of combination of ball milling process (MA) and combustion synthesis in ultrahigh gravity field, so that combustion mode has transfer from steady SHS to thermal explosion, and reactive blend of mass 1200 g and adiabatic temperature 3200 oC was completely consumed in about 0.20 s and the average linear combustion velocity reached about 750 mm · s-1.
As discussed above, by combining ball milling processing with combustion synthesis in ultrahigh gravity field, the temperature of full-liquid products increase sharply because combustion mode transfers thermal explosion from steady SHS under the dual influence of mechanically-activated powder and ultrahigh gravity field, and liquid-liquid separation of TiC-TiB2 and Al2O3 liquids is promoted due to the enhancement of Stokes flow of Al2O3 droplets in TiC-TiB2 liquid, as shown in Eq. 3 and Fig. 2, resulting in the sharply-reduced Al2O3 inclusions in ceramic matrix, so shrinkage cavities are dramatically reduced, and high relative density of the solidified TiC-TiB2 composite is achieved correspondingly.
It is considered that taking balling milling processing to mechanically activate powder blend yields the sharply-increased temperature of full-liquid product by reducing ignition temperature and promoting combustion mode transfer from steady SHS to thermal explosion, thereby not only accelerating liquid-liquid separation of immiscible TiC-TiB2 liquid and Al2O3 droplets, but also increasing nucleation rate of TiB2 leading phases due to the enhanced undercooling of TiC-TiB2 melt.

Generally, fabrication techniques used to preparation TiC particulates reinforced iron based composites involves powder metallurgy [1, 3], aluminothermic reduction [4], traditional casting [5] and self-propagating high-temperature synthesis (SHS) [3, 6, 7], etc.
In the present study, TiC particles reinforced iron base composite was prepared utilizing the self-propagating high-temperature synthesis (SHS) route.
The purpose of the present investigation was to examine the effect of heating temperature of quenching on the microstructures and properties of in-situ TiCp/Fe composite produced by SHS route.
The mixture powder was mixed using a ball-grinding mill for 12 h, and then were uniaxially pressed into cylindrical preforms (12mm diameter and 15~20 mm length) under a pressure about 32~40 MPa to obtain densities 65±5% theoretical density.
The steel melt was prepared in a 5kg medium-frequency induction furnace in air environment, and then the steel melt with a temperature of about 1600ºC was poured into the sand mold to ignite the SHS reaction of the performs.

Recently, the low-temperature combustion synthesis (LCS) technique developed from self-propagating high-temperature combustion synthesis (SHS) and wet chemical techniques has been proved to be a novel, extremely facile, time-saving and energy-efficient route for the synthesis of ultrafine powders [6-8].
Mg(NO3)2·6H2O Al(NO3)3·9H2O CO(NH2)2 Mixing and grinding Paste Combustion Thermal explosion Spinel Fig. 1 Flow chart for the preparation of MgAl2O4 The phase purity and homogeneity of prepared powder was characterized by X-ray powder diffraction (XRD) with Cu Kα radiation at 30 kV and 30 mA.
The calculation of adiabatic flame temperature in LCS is more difficult than that of SHS, because the reaction of organic compounds in the LCS process is complicated, and relevant thermodynamic data of are scarce.
According to Merzhanov’s [11] empirical criterion for SHS, if Tad<1227, combustion does not occur, and if Tad >2227, self-propagating combustion occurs.

Furthermore, there exists the possibility to easily perform a combination with self-propagating, high-temperature synthesis (SHS): when a powder mixture is heated, then reaction may start at a certain temperature.
As SHS products are porous due to the evolution of gases by exothermic reaction, subsequent explosive compaction (HEP) allows the consolidation of the product.
On the other hand, if during heating of the powder mixture the detonation of the explosive charge is started, the reaction in the powder mixture is initiated: it is a shock assisted SHS [2].
Pieces were taken from the samples for metallographic investigation and for mechanical testing by means of sparc erosion technique and by grinding.

Research of the magnetic grinding technology focused on three aspects: grinding equipment, magnetic abrasive and technical parameters.
There are many kinds of methods for preparing magnetic abrasives, such as traditional sintering [3], bonding [4], SHS [5], and plasma powder melting preparation methods.
In other words, the magnetic abrasive shows efficient grinding ability in a certain lifetime.
The grinding ability of the various particles was detected.
The trend of the grinding ability of abrasive with different size range is similar.

To obtain these coatings on 65G steel from a modified mixture consisting of 2Al+B2O3, containing 25 and 45% of flux P-0.66, a combination of the SHS process and HFEC heating was used in our study.
The plates had dimensions of 50*100*5 mm and after drying were subjected to induction heating according to the same scheme: after the moment of the SHS process, the generator power was reduced by 25% and the heating continued for another 60-80 seconds.
The following machines were used in the preparation of samples: manual cutting, manual grinding and sharpening machines.
Data on the results of studying the structure of coatings obtained in the framework of using the SHS process during induction heating of modified mixtures (flux P-0.66 content on 65G steel is 25 and 45%) are presented in figures 1-8.

Gyeong Sang National University, 660-701, Gazwa-dong 900, Chinju, Korea ** Kaya AMA Co, 626-862, Baekrok-Li 1010-1, Habuk-Myun, Yangsan-Si, Lorea. 1 ais@gsnu.ac.kr Keywords : TiC, TiH2 Powder, Carbothermal reaction, Spark Plasma Sintering Abstract The TiC cermet widly used for high hardness working dies and tool materials was fabricated by carbo-thermic reduction of thtania-precusor or self-propergating high temperature synthesis(SHS) reaction.
The most conventional methods used to fabricate commercial powders are by carbo-thermal reduction of mixture(TiO2 and carbon black) and self-propagating high-temperature synthesis (SHS) reaction.These methods should be able to reduce the total cost for using TiO2 powders as raw material[5].
In this study, the TiC powders was synthesized by self-propagating SHS reaction, and characterized the particle size variations during the high energy ball milling process and phase transformation after heat treatment process in TiH2-C system.
The grinding media was stainless steel ball with 5mm diameter.

Increasing high gravity acceleration not only promoted the combustion mode transfer from steady SHS mode to explosive one through enhancing the deposition of liquid product toward unreacted blend, but also accelerated liquid-liquid separation of TiC-TiB2 / Al2O3 droplets and subsequent formation of layered melt through enhancing Stokes flow in mixed liquid products, thereby reducing sharply Al2O3 inclusions and shrinkage cavities in solidified TiC-TiB2 composite.
Therefore, TiC-TiB2 ceramic composites are attractive for application as advanced structural materials, and many methods, such as reactive sintering, reaction hot pressing, spark plasma synthesis, transient plastic phase processing, and self-propagating high-temperature synthesis (SHS), also termed combustion synthesis (CS) have been developed for the synthesis of such TiC-TiB2 ceramic composites [1].
Finally, the ceramic discs of 150 mm in diameter and 20 mm in thickness were obtained after the samples were taken out of the crucibles and the oxide slag at the top of the sample was eliminated by grinding.
Hence, it is considered that the enhanced high-gravity field would promote combustion mode to transfer explosive combustion mode from steady SHS one, thereby heating the products to be close to adiabatic temperature of combustion system by increasing energy accumulation of combustion process.
Increasing the high-gravity acceleration promoted heat conduction, mass transport and momentum transfer between reactant particles through accelerate the deposition of liquid products towad unreacted blend, and brings about combustion mode transfer from steady SHS mode to explosive one, thereby making the actual temperature approach the adiabatic temperature.

The modeling explained the very efficient grinding that takes place at low velocity ratios; indeed, the grinding included a more chaotic motion of the balls and, possibly, much stronger interactions.
Characteristics of the grinding bodies.
Mass fraction of the adhered material versus the surface area of the grinding bodies.
Grogorieva, Influence of Mechanoactivation on the Phase and Structure Formation Processes in SHS, Novosibirsk, Parallel, 2008.
Korchagin, Experimental study of the mechanism of interaction of SHS reagents and the development of the scientific foundations for synthesis of nanocomposite materials with a ceramic reinforcing phase, PhD theses, ISSC SB RAS, Novosibirsk, 2007.

Grinding was performed in 240 minutes for high-energy milling process and 280 minutes for reactive milling powders.
Since a reaction is highly exothermic, it can take place abruptly after a certain milling time and, once started, it proceeds in a self-sustained way, similarly to the so-called self-propagating high-temperature synthesis (SHS) process.
In this case the mechanical properties are directly related to the efficiency of grinding. [5] For many materials the refinement is possible only if the energy transferred to material is enough to produce cold welding and fracture of the particles [[] T.S.
Dreizin: Acta Materialia Vol. 53 (2005), p. 2909. ], this means that during milling the impact energy of grinding media to powder should be enough to break hardened particles.
The high energy mill of particles leads to formation of strong agglomerates or aggregates of reaction products and grinding NbC.