Papers by Author: Ivan A. Bataev

Abstract: The structure of composites formed by explosive welding of thin sheets of tool and austenitic steels was studied by structural analysis methods. It is shown that the quenching and tempering of composites leads to the formation of complicated structure containing, along with layers of dissimilar steels, layers with new chemical compositions. Due to the structural changes there is an 2-fold increasing of impact toughness.

Abstract: The aim of the work was to clad Ti-Ta-Nb coating on a substrate of pure titanium. Cladding was carried out by non-vacuum electron-beam treatment. As a result a good quality coating thickness of about 2 mm was obtained. Microstructural and microhardness tests were conducted. Dendritic structure and the borders of the former grains of β-phase were revealed. At the microlevel, the coating has a martensitic structure. The average hardness of coating is about 4000 MPa.

Abstract: Commercially pure aluminum and commercially pure titanium plates have been explosively welded and annealed at temperature of 630 °C for 5, 20, 50 and 100 hours. The investigation of intermetallic formed during explosion welding and heat treatment processes has been carried out. The metallographic studies showed variation in the intermetallic volume fraction according to the deformation degree of different interfaces. Moreover the relation between the intermetallic layer thickness and time of explosively welded “Al-Ti” composite annealing has been found. The X-ray analysis reviled that intermetallic layer formed during the heat treatment process consisted of Al₃Ti compound.

Abstract: Multilayer materials produced by explosive welding of low carbon steel were investigated. Non-uniform structure of interlayer boundary was characterized using visible light microscopy, SEM and TEM. It was shown that 4 zones with different structure and mechanical properties present in the welded seams. To estimate fatigue properties of the multilayer materials kinetic diagram of fatigue failure were used. It was revealed that larger boundary waves give more significant contribution to fatigue crack resistance. In experiments carried out in the current research number of cycles to failure of multilayer materials was higher than those for bulk materials.

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.