Mechanisms of plastic deformation of zirconium-based alloys upon uniaxial compression under different temperature-rate conditions

Based on the results of X-ray diffraction analysis of texture of the Zr-1% Nb and Zr-2.5% Nb model alloys compressed uniaxially at temperature corresponding to the β and α + β fields of the phase diagram, the mechanisms responsible for plastic deformation have been determined. These are the crystallographic slip in the β-Zr and α-Zr grains and also the diffusional mechanism of mutual displacement of crystallites along interphase boundaries, which is activated upon the α ? β phase transformations and is the basis of superplasticity. The contribution of each mechanism to the formation of specimen texture depends on the temperature-rate regime of compression.     

The size effects in hardness of polycrystalline niobium

The indentation size effect on the hardness of polycrystalline niobium has been studied. A relationship between the material hardness and the indenter mark dimensions is established in a broad range of indentation depths (20 nm–70 μm).     

Textural changes at the tip of a moving crack during fracture of sheet Zr-1% Nb alloy

Moscow Engineering-Physics Institute. Translated from Atomnaya Énergiya, Vol. 73, No. 8, pp. 121-128, August, 1992.     

Finite element simulation of microindentation

Finite element models are created to describe the testing of a material by a Berkovich indenter. The results of calculations by these models are compared to experimental data on indentation of the same material (grade 10 steel). The experimental and calculated data agree well with each other. The developed models for an indenter and the material to be tested are used to find the laws of behavior of a material during indentation. The state of stress in the material under an indenter is studied by various methods. The indentation results are plotted versus the mechanical properties of a material.     

Use of Hafnium in Control Elements of Nuclear Reactors and Power Units

The expedience in the use of hafnium for control elements of a nuclear reactor is considered. The requirements of various producers on the chemical composition and mechanical properties of nuclear-purity hafnium are presented. Results of studies of the strain resistance and ductility characteristics of hafnium are discussed depending on the temperature and the deformation rate. The dependence of the hafnium hardness on the degree of deformation and on the annealing mode is presented. Results of a texture analysis are used to judge the effect of deformation and heat treatment on the anisotropy in the properties of hafnium. The developed process is used for the production of hafnium parts at VNIINM, i.e. hafnium plates are fabricated for the attachment unit of automatic control assemblies (ACA) for VVÉR-440 reactors.     

Formation of crystallographic texture in titanium nickelide single crystals during rolling

The texture formation in the single crystals of the Ti-48 at % Ni-2 at % Fe alloy rolled at a temperature of 350°C up to a strain of 80% in eleven different initial orientations is examined. There are three stable initial orientations that remain unchanged in rolling: {011}〈011〉, {111}〈011〉, and {111}〈112〉. The TiNi single crystals are shown to be deformed by means of a combined action of slip in systems {011}〈001〉 and twinning in systems {114}〈221〉 and {118}〈441〉. The types of formed rolling texture in the single crystals depend on their initial orientation and strain.