Papers by Author: Anatoly Bataev

Abstract: A method of surface alloying of titanium substrates with tantalum in order to obtain corrosion-resistant layers is described. An electron beam injected into the atmosphere is used as a power source. A powder layer containing a composition of alloying components and a fluxing agent was placed on the surface of a Ti plate. The plate exposed to a scanning beam was moved at a speed of 1cm/sec. The scanning range was 5cm, the scanning frequency was 50 Hz and the beam power was 33.5 kW. To enhance the degree of alloying the coating procedure was repeated up to 4 times. Alloyed layers 2-3 mm thick containing up to 40 wt % Ta were obtained. The rate of corrosion in HNO₃ depends on the Ta concentration in the deposited material. It is tens and hundreds times lower than the rate of corrosion of unalloyed titanium for all coatings. Surface deposition by the proposed method can be used to protect internal surfaces of chemical reactors operating in media containing aggressive acids at increased temperatures up to the boiling temperature.

Abstract: Structure, microhardness and fracture features of coatings produced by atmospheric electron-beam cladding of amorphous boron were investigated. The coatings were produced by cladding of one, two and three layers of powder. Produced coatings thickness is 550, 750 and 900 μm respectively. The peak level of microhardness is 14000…16000 MPa. By the means of XRD analysis it is stated that the main phases of strengthened layers are FeB and Fe₂B borides and eutectic (α-Fe + Fe₂B). The coatings after one layer cladding have non-uniform structure with microvolumes having lack of borides. Three-layered coatings are noted for their high brittleness. The best properties are presented by two-layer coatings.

Abstract: The structure and mechanical properties of the laminates produced by explosive welding of low carbon steel were investigated. The maximum number of layers in the composites was 21. It was shown that the structure of the composite is not uniform across the thickness of the layers and along the boundaries in the shape of the wave. Transmission electron microscopy revealed that the sizes of the grain-subgrain clusters forming in the weld adjacent zones are about 100…400 nm. The maximum temperature was reached in the areas of the vortices. High-strength martensite was formed in these zones in the process of cooling. The strength properties and toughness of the com-posite is almost 2 times higher compared with the properties of the original plates. It was shown that the boundaries of welds are the barriers inhibiting the development of fatigue cracks.

Abstract: A structure of a carbon steel specimen after explosive loading is investigated. The loading was executed by Mach stem, formed in high explosive charge that was preliminary compressed by advanced wave in ceramic bar. In the original condition the specimen had a typical for low carbon steel ferrite-pearlite structure. Metallographic analysis has shown that during the process of the explosive loading the following structural changes took place: formation of numerous deformation twins in both ferrite grains and pearlite colonies (i.e. in two-phase structure); formation of extended bands of localized deformation, which are not crystallographically connected with the original ferrite-pearlite structure; fine grains formation in zones of severe plastic flow. The size of the ferrite grains is by an order of magnitude less than the original grains size. According to the authors’ opinion, above-noted structural peculiarities demonstrate that loading conditions achieved in the current loading scheme differ from common. The phenomenon of non-typical twinning in heterogeneous structure (pearlite) indirectly evidences that extremely high stresses and strain rates took place in the specimen during the loading.