Simulation of stress-strain state at the boundaries of a bimetallic composite to determine tear-off resistance

Simulation modeling of the deformation under mechanical action on the sample workpiece of the steel-aluminum bimetallic composite material with a thin aluminum intermediate layer was performed. The stress-strain state along the boundaries of the joint at which the sample workpiece layering occurs was determined. A series of computational experiments with varying the specific work value of the layering under separation conditions was implemented. The level of stresses, leading to the separation of the bimetallic compound, is estimated using the energy criterion. The dependence of the rupture strength along the ring contour on the specific work value of the layering varied in the range of 0.1-0.2 N/mm was calculated. It was established that for the studied variants of the computational experiment, a rigid stress state with the predominance of normal tensile stresses is implemented in place of the beginning of the layering. © Published under licence by IOP Publishing Ltd

Studying damage accumulation in martensitic corrosion-resistant steel under cold radial reduction

Cold radial reduction of specimens made of the Kh17N2 corrosion-resistant martensitic steel is studied on a lever-type radial-forging machine (RFM). The mechanical properties of the deformed specimens, the "damage accumulation - strain" relation in the specimens are obtained with the application of hydrostatic and fractographic methods for fractured specimens. The damage of the Kh17N2 corrosion-resistant steel is evaluated as a result of an experimental study considering the data of simulation by a complex finite element model of cold deformation on a lever-type RFM. © 2017 Author(s)

The additive technology to obtain a three-dimensional model of the 81Cu-19Ni alloy

This paper is devoted to the selective laser smelting (SLS) method description for the article made of powder of a Cu81-Ni19 copper-nickel alloy and the study of the structure and characteristics of the three-dimensional article made using additive technology. To make a 3D model the copper-nickel alloy powder was produced in our laboratory. The chemical composition, microstructure, density, surface roughness and microhardness of an article made of powders of a Cu81-Ni19 copper-nickel alloy are considered. A comparative analysis of the structure, physical and mechanical properties of a sample obtained by the SLS method and the annealed rolled plate was carried out. The article microstructure is characterized by the absence of a typical signs of a crystalline structure and contains elements of a quasi-amorphous state. At the same time, the obtained material differs from the standard monolith billet with a lower surface roughness and a higher hardness values while maintaining almost the same density indices. © Published under licence by IOP Publishing Ltd

Elastic properties of mono- and polycrystalline hexagonal AlB2-like diborides of s, p and d metals from first-principles calculations

We have performed accurate ab initio total energy calculations using the full-potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange-correlation potential to systematically investigate elastic properties of 18 stable, meta-stable and hypothetical hexagonal (AlB2-like) metal diborides MB2, where M = Na, Be, Mg, Ca, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ag and Au. For monocrystalline MB2 the optimized lattice parameters, independent elastic constants (Cij), bulk modules (B), shear modules (G) are obtained and analyzed in comparison with the available theoretical and experimental data. For the first time numerical estimates of a set of elastic parameters of the polycrystalline MB2 ceramics (in the framework of the Voigt-Reuss-Hill approximation), namely bulk and shear modules, compressibility, Young's modules, Poisson's ratio, Lame's coefficients are performed.Comment: 24 pages, 3 figure