Research of structure and properties of Cu-Pb-Cu composite interface, obtained by technology of pack rolling of the pair of mutually insoluble metals, was performed using the methods of metallography, micro-and nano-hardness, mechanical tests, energy-dispersion elementary analyses. The work was aimed at the analyses of possible mechanical mechanisms of mass-transfer, determining the hardness of metal joint in conditions of absence of inter-diffusion. It was shown that different intensity of mass transfer of copper and lead takes place through the composite interface, which corresponds to the results obtained on the other system of dissimilar materials-copper-niobium. Qualitative explanation of these patterns was offered on the basis of more intensive plastic flow of fusible compound of the composite in conditions of roll-bond joining.
Mechanisms taking place while hot rolling in vacuum of dissimilar materials joined in solid phase are described. It is shown that at joining of materials in solid phase redistribution of atoms from one material into another occurs on the interface of joining. On the base of calculation and experimental results it is concluded that the ultimate strength of the interface of joint is always higher than the ultimate strength of less durable material. Pair zirconium-stainless steel SS (Type AISI 321) and carbon steel (Type C22E) those are used in nuclear power are investigated.
Elementary convection cells (ECC) are formed in horizontal layers of liquid heated from below, and they are experimentally investigated in this work. Results of experimental studies were adequately described by the theoretical model of ECC. It is shown that the addition of aluminum powder to oil transforms oil to a suspension, such that boundary conditions on the solid wall can be regarded as free because there is a slip through the tape of pure oil. Change in the character of boundary conditions is confirmed by the results of numerical processing of experimental results on formation of convective rings on the layer surface by other authors. Two independent methods for determining the velocity of mass transfer in cells with various diameters are described in the article. For cells with a large diameter (17 mm), the maximum velocity of mass transfer was measured at the upper boundary on a deflection angle of the probe. Measured in this way velocity was equal to V<sub>Oil</sub> ≈ 0.2 mm/sec. For cells with a smaller diameter (2 mm), the velocity of oil on the surface of a cell was measured using an optical method and constituted the value from 3.5 mm/s to 5.2 mm/s.
The paper presents the study of hierarchy of deformation wave-processes from nano-to macro-structural level, which takes place in dissimilar materials, bonded by high-temperature vacuum rolling in solid phase. The focus was on the processes that occur on the interface of the bonded materials: mass trasfer of impurities and alloying elements stimulated by deformation, the study of nano-and micro-hardness.
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