The deformation behavior of high-chromium steel (0.4%C-0.6%Si-0.55%Mn-12.5%Cr) of martensitic structure upon quenching and of sorbitic structure upon high-temperature tempering has been investigated. Each of the states is shown to be represented by a particular stress-strain curve. The stress-strain curve for the steel in the martensitic state consists of a single linear-hardening stage, whereas in the sorbitic state, it exhibits a three-stage deformation pattern. The plastic flow of the examined material in the two states has been found to be of a localized character. The evolution of localized-strain center distributions follows the law of plastic flow, i.e., it depends on the deformation stages in the stress-strain curve. The fracture process is determined by the kinetics of the localized-strain centers in the final (prefracture) deformation stage in the stress-strain curve.

The paper presents a metallographic study of aluminum alloy welds produced by friction stir welding. The weld structure is described for two alloys: Al-Cu and Al-Mg. It is shown that friction stir welding provides a fine-grained structure of the weld. The phase composition of the weld metal for the studied alloys is defined. Differences in the structure and distribution of second-phase particles in the weld metal are shown. The weld zone of Al-Cu alloy consists of equal size grains, with intermetallic particles located along the grain boundaries. The weld structure of Al-Mg alloy is banded, with alternating layers consisting of different size grains.

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The process of plastic deformation in ultrafine grain titanium is considered. Using the methods of speckle photography and X-ray diffractometry, the distributions of local strains and of local elastic distortions were examined for the test sample work. It is shown that the method of atomic-force microscopy can be used effectively for qualitative and quantitative assessment of ultrafine grain material structure.