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14XV International Symposium on Self-Propagating High-Temperature Synthesis
OBTAINING OF COMPOSITE MATERIALS BY SHOCK-WAVE TREATMENT AND SHS
A. Yu. Malakhov*", I. V. Saikov", V. G. Salamatov", and S. A. Seropyan"
aMerzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, Moscow, 142432 Russia *e-mail: [email protected]
DOI: 10.24411/9999-0014A-2019-10092
Cermet combine the properties of ceramics (high hardness, heat resistance) and metal (thermal conductivity, plasticity). It is widely used in aerospace and other fields of technology. The traditional method of obtaining cermet includes the following stages: a long high-temperature sintering of powder compositions to obtain ceramics (e.g., TiC and TiB2) and further sintering of metal powder (e.g., Ti, Ni, Al). Application of combustion synthesis [1] upon receipt of cermet powder systems is given much attention lately [2]. Interest is due to the possibility of the synthesis of materials in one stage and an external heat source due to the internal energy of the system. For some areas of engineering, as well as for individual tasks of the military-industrial complex (development of the armour material) prospectively the use of layered metal-ceramic composites. However, it is difficult to obtain because of the complexity of combining metal and ceramics in the same material. From this point of view seems promising Association or combination of two technologies: shock wave SHS-compacting materials and thermochemical synthesis to obtain composite materials. When this realization of synthesis of reactive powder mixtures is possible both at the stage of shock-wave treatment, and subsequent heat treatment and at rolling [3].
Study process shock wave loading was carried out on an example of powder systems Ti-B-Ni and Ti-C-Ni. The components of the reaction systems were titanium PTS powders with different particle sizes, boron B-99A, nickel PNE-1 and C carbon (T-800). Powder mixture composition of 90% (Ti + 2B) + 10% Ni (Tad = 3144 K) + 80% (Ti + C) + 20% Ni (Tad = 2647 K) for 2 h were mixed in a mixer "Turbula" type and molded in the form of cylinders with a diameter of 10 mm with a relative density of .,65. Mechanical activation of the green mixtures was carried out in a planetary ball mill AGO-2. The molded samples were placed in a metallic matrix (Fig. 1.a) with a pre-made blind holes (cells). The loading samples were throwing steel a planar flyer, which is accelerated by an explosive charge to velocities of 0.7; 1.0; 1.5 km/s according to the scheme indicated in Fig. 1b. Initiation detonation conducted from the center axis of the matrix thus provides the same loading conditions in all cells.
(a) (b)
Fig. 1. Experimental scheme: (a) metal matrix with filled cells; (b) scheme of initiation the SHS by steel planar flyer.
iSHS 2019
Moscow, Russia
The experiments investigated the effect on the initiation of the synthesis of the following factors: dispersion, density, mechanical pre-activation, throwing velocity a planar flyer.
After the shock wave loading depressurization assembly and removal of the cells were detected products. Samples were removed from the metal matrix and investigated by XRD, optical and electron microscopy. Because of experiments, it was determined that the rate of metallic a planar flyer of 1.5 km/s is achieved by stable high thermochemical synthesis SHS compositions. At speed of 1.0 km/s is required for mechanical activation of the initial synthesis mixture of powders and under the conditions of 0.7 km/s initiation SHS compositions occurs. Thus, in this study, conditions of shock wave loading under which passes thermochemical synthesis of mixtures of powders of 90% (Ti + 2B) + 10% Ni + 80% (Ti + C) + 20% Ni was determined and cermets TiB2-Ni and TiC-Ni were prepared.
The research was supported by the Russian Foundation for Basic Research (project no. 19-08-00754 A).
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2. A.V. Istomin, V.E. Nadutkin, V.E. Grass, of Ti3SiC2 -based ceramic matrix composites by a powder-free SHS technique, Ceram. Int., 2013, no 39, pp. 3663-3667.
3. M.I. Alymov, L.B. Pervukhin, A.S. Rogachev, O.L. Pervukhina, I.V. Saikov, Combination of SHS and the shock-wave compaction for the production of composite materials, Lett. Mater., 2014, no. 4, pp. 153-158.
