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Titanium alloys have high specific strength and corrosion resistance, which have promising applications in industry. However, the machinability of titanium alloys is limited due to their crystal lattice and physical properties. Thus, in recent years, the superplastic forming of titanium alloys has been intensively developing, in particular, forming at low temperatures and/or high strain rates. In this work, a tensile test of low-cost Ti-2Fe-0.1B alloys was carried out at a temperature of 550~750 °C and a strain rate of 1 × 10−3 s−1~1 × 10−2 s−1. The results showed that the alloy exhibited good superplasticity even at a high strain rate (1 × 10−2 s−1) and a low deformation temperature of 550 °C; the elongation of the alloy in this state reached 137.5%. The high strain rate sensitivity coefficient m (0.3) and the maximum elongation (452%) were obtained at a strain rate of 1 × 10−3 s−1 and a temperature of 750 °C. Characteristics of the microstructure showed that during superplastic deformation, the recrystallization and grain boundary sliding of the alloy phases were accelerated, which could be ascribed to the effect of the element Fe. At the same time, the TiB phase located around the primary elongated α grains could also induce dynamic recrystallization and dynamic globularization during deformation. [ABSTRACT FROM AUTHOR]

Presents a study which performed quantitative x-ray diffraction measurements on a nanocrystalline copper sample made by severe plastic deformation. Experimental results; Discussion and conclusions.

The microstructure and mechanical properties of joint welds formed by linear friction welding (LFW) in in Al-Cu-Mg alloy was investigated. Joint welds of two samples of rectangular shape do not possess any macroscopic defects and are characterized by high strength. The substantial transformation of the microstructure occurs in the weld zone as a result of plastic deformation and deformation heating during LFW. [ABSTRACT FROM AUTHOR]

Abstract: Regardless of the origin of structure irregularities of materials, the recognition of their spatial distribution in a sample or constructing elements is a great research problem. One of the most effective and non-destructive tools used for this purpose is the X-ray diffraction technique, assisted by an appropriate experimental method and data processing. The work presents the results of investigations of planar distribution of crystallographic texture and stress irregularities manifested by changes of diffraction effects registered by the X-ray technique. As an example, the introduced method is tested on a titanium rod after severe plastic deformation process. [Copyright &y& Elsevier]

A model is proposed for the formation of the substructure in polycrystals during plastic deformation. According to this model, fragmentation of a grain occurs through the formation of a system of diagonal low-angle boundaries, which originate at the edges of a rectangular grain. Misorientation boundaries form through relaxation of a nonsymmetric junction quadrupole disclination configuration accumulated at the grain corners under severe deformation when the disclination strength reaches a certain critical value. The energetics of this process is analyzed. A general case is considered where the disclinations at the junctions of the chosen grain differ in strength. The energetic approach used makes it possible to determine the misorientation angle ωx of the resulting boundaries corresponding to the maximum energy gain and to find the dependence of this angle on the degree of asymmetry of the quadrupole configuration of junction disclinations. According to the proposed model, the splitting of a grain with a short edge greater than 0.5μm is energetically favorable and decreases the latent energy of the grain for any ratio between the junction disclination strengths if the grain length-to-width ratio is less than 30. It is shown that the minimum possible grain size in the proposed model does not exceed 0.1μm. © 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]