Joining of Titanium and its Alloys with Aluminum Alloys by Friction Stir Welding

This article is devoted to the study of the mechanism of formation of dissimilar welded joints Ti-2Al-1.5Mn, pure titanium (Ti35A) and aluminum (Аl (pure), Аl-6Mg-0.5Mn) alloys obtained by friction stir welding (FSW). The investigated microstructure of the weld joint nugget (WN), zones of thermo mechanically affected zone (TMAZ) and heat affected zone (HAZ) formed at FSW between Ti-2Al-1.5Mn, Ti35A and aluminum (Аl (pure), Аl-6Mg-0.5Mn) alloys. Zones of welded joints at FSW are formed in the mode of structural superplasticity (SP) with a specific shear-band layered structure with alternating layers. The achievement of superplastic state (SPS) in the formation of WN, TMAZ, HAZ is provided by the step–by–step transformation of various mechanisms of plastic deformation in the mode of simple, collective, abnormal dynamic recrystallization, prepared by the processes of dynamic return, polygonization with the transition to post-dynamic recrystallization by the mechanisms of Bailey–Hirsch, Kahn-Burgers-Taylor. At FSW aluminum and titanium alloys with polymorphism, SPS is supported additionally due to recrystallization by twinning and as a result of phase transformations of alpha-gamma or alpha-beta phases.

Связь явлений переноса с характеристиками кластерной структуры воды

Using a statistical approach, we have estimated the size of water clusters and the number of free molecules participating in transport phenomena. The sizes of clusters and the number of molecules in them, as well as the number of free water molecules and their mean free paths, have been determined using experimental data on the temperature dependence of viscosity and density of water. It has been concluded that a temperature of 36.6°C is a special point in the range of 0–100°C. At temperatures higher than this value, the binding energy of a molecule with a cluster decreases abruptly, while the concentration of free molecules sharply increases. Quantitative data have been compared with the parameters of the superplastic state of titanium. As an example, we consider metabolism in functioning of erythrocytes of blood in an adult human.

Solid State Diffusion Welding by Superplastic Coordinate Deformation between Vacuum Spray Fusing Alloy G111WC and Steel Substrate

This paper discusses the issues about the incorruptibility of industrial dies, mainly researches the G111WC and G112WC mixed alloy layer sprays fusing on the surface of industrial dies under the vacuum condition and the solid phase welding-on mechanism of the mixed alloy layer under superplastic state. It points out that when W≈1 ( W is strain ratio of coating and substrate ) and within the range of the generatrix’s superplasticity, the layer and the generatrix will realize the solid state diffusion joining by superplastic coordinate deformation, which leads to an effective welding.