Olga V. Antonova

Optical (OM), scanning electron (SEM), and transmission electron microscopy (TEM) were used to investigate microstructure in the interface zone of 09Mn2Si steel/Ti joint obtained by means of explosion welding. It was shown that the bonding interface had a wavy appearance. Moreover, it was observed that grains near the interface were elongated in parallel to the explosion direction. TEM study has demonstrated that the microstructure typical of states after severe plastic deformation (SPD) is observed in the areas where materials in solid are welded. These are mesoscopic-level defects: fragmented deformation microbands with high number density of microscopic-scale defects, dislocations, and a cellular microstructure. The sizes of individual deformation bands generally varied in a range of 200–400 nm, which well enough correlates with the distance between dents at the bonding interface. This gives grounds to presume that the bands can play an important role in the explosion welding processes. Near the bonding zone, finely dispersed precipitates of Ti₄Fe₂O are found in titanium, as well as iron carbides of Fe₃C—in steel area.

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The possibility of severe plastic deformation of the Cu-47Pd (at %) alloy by room temperature rolling to high degrees without intermediate anneals has been shown. The microstructure and...

Results of studying structure of the transition zone for a number of joints produced by explosive welding are presented. The joints of dissimilar metals (titanium-orthorhombic titanium aluminide,...

The microstructure of a bimetallic joint made by explosion welding of orthorhombic titanium aluminide (Ti–30Al–16Nb–1Zr–1Mo) with commercially pure titanium is studied. It is found that the welded joint has a multilayered structure including a severely deformed zone observed in both materials, a recrystallized zone of titanium, and a transition zone near the interface. Typical elements of the transition zone—a wavy interface, macrorotations of the lattice, vortices and tracks of fragments of the initial materials—are determined. It is shown that the observed vortices are formed most probably due to local melting of the material near the contact surface. Evidence for this assumption is deduced from the presence of dipoles, which consist of two vortices of different helicity and an ultrafine duplex structure of the vortex. Also, high mixing of the material near the vortex is only possible by the turbulent transport whose coefficient is several orders of magnitude larger than the coefficient of atomic diffusion in liquids. The role played by fragmentation in both the formation of lattice macrorotations and the passage of coarse particles of one material through the bulk of the other is determined.

The possibility of the reconstruction of the shape of the potential relief (single-valley-two-valley) and its parameters using the effect of self-blocking has been demonstrated. Allowed and forbidden...

The effect of the degree of deformation upon torsion under quasi-hydrostatic pressure on the structural and phase transformations in the V95 alloy has been studied by the methods of electron...