Mechanical Behavior of Nanostructured and Ultrafine-Grained Metal Alloy under Intensive Dynamic Loading

Researches of the last years have allowed to establish that the laws of deformation and fracture of bulk ultrafine-grained (UFG) and coarse-grained (CG) materials are various both in static and in dynamic loading conditions. The influence of average grain size on the yield stress, the tensile strength, and the compression strength was established for metal alloys with a face-centered cubic (FCC), a body-centered cubic (BCC), and a hexagonal close-packed (HCP) structures. The study of the microstructure of the alloys after severe plastic deformation (SPD) by the electron backscatter diffraction (EBSD) technique showed the presence of a bimodal grain size distribution in the UFG alloys. Metal alloys with a bimodal grain size distribution possess a negative strain rate sensitivity of the yield stress and higher ductility at quasi-static strain rates. In this chapter, we will discuss the regularities of deformation at high strain rates, damage, and fracture of ultrafine-grained alloys

Influence of grain size distribution on the mechanical behavior of materials in a wide range of strain rates

This work compares the mechanical behavior of alloys with influence of grain siz

Deformation and damage of Fe-Cr steels in a wide temperature range

The deformation and damage of a high chromium steels in a wide temperature range wa

Damage of high-chromium steels under deformation in a wide temperature range

High-chromium steels have high strength properties, corrosion properties and resistance to neutron irradiation, thereby are considered as promising steels for nuclear reactors of generation IV. The deformation and damage of high chromium steels in a wide temperature range was studied by numerical simulation method. A model was proposed to predict the deformation and damage of high chromium steels under quasi–static loading within the temperature range from 295 to 1100 K. It is shown that the ductility of high-chromium steels increases proportionally to temperature in the range from 750 to 1100 K due to the growth of α′-phase precipitates

Pentamode metamaterials under dynamic loading

The field of metamaterials has grown considerably in the last few decades due to the advances in new manufacturing technologies. Metamaterials currently are of interest for a wide variety of applications including damping systems. This work is aimed to evaluate dissipative effect of pentamode metamaterials subjected to dynamic loading. The results of numerical modelling of the mechanical behavior of pentamode metamaterials from alpha titanium alloys are received and compared with available experimental data. The model of inelastic deformation and ductile damage criterion are used to describe the ductility of the unit cell of metamaterials in a wide range of strain rates, temperature and stress triaxiality. A methodology for analyzing the energy dissipation due to inelastic deformation of metamaterials at high strain rates is presented. It is shown that the values of the energy dissipation coefficient during uniaxial dynamic compression of the pentamode metamaterial are 1.5 times higher than for the bulk alloy counterpart

Numerical simulation of the mechanical behaviour of ultrafine - and coarse - grained Zr-Nb alloys over s wide range of strain rates

This paper presents the results on the development of theoretical methods of evaluation and prediction of mechanical properties of Zr–Nb alloys over a range of strain rates from 10−3 to 103 s−1. The mechanical behavior of coarse- and ultrafine-grained Zr–1Nb (E110) was investigated numerically. The ranges of strain rates and temperatures in which the mechanical behavior of Zr–1Nb alloy can be described using modified models of Johnson–Cook and Zerilli–Armstrong were defined. The results can be used in engineering analysis of designed technical systems for nuclear reactors

Пластическое течении легких ГПУ-сплавов при линейной сварки трением

Целью данной работы было исследование массопереноса и закономерностей пластического течения в зоне формирования сварного шва титанового сплава методом численного моделирования. Сварку сплавов осуществляли методом ЛСТ (линейная сварка трением). Этот метод хорош тем, что позволяет добиться высоких прочностных характеристик вблизи поверхности контакта без доведения сплава до плавления и без существенного изменения химического состава сплава. Для численного моделирования процесса ЛСТ использовался метод гидродинамики сглаженных частиц (SPH) [1,2]. Моделирование процесса ЛСТ осуществлялось методом SPH с использованием пакета LS-DYNA (ANSYS WB 15.2) и разработанного модуля определяющего уравнения