Papers by Keyword: Pulse Loading

Abstract: The behavior of the ferromagnetic alloy based on Fe-Cr-Co under high-speed loading is presented. Three types of samples were prepared with different pre-treatments: quenching only; quenching and ageing; and quenching and ageing under an intense external magnetic field. The sub-microsecond impact load was created by the installation for the electrical explosion of foils. The developed method of loading allows a pressure pulse to be registered before impact on a flat sample and after its exit to a free surface of this sample. Changes in the mechanical properties of the ferromagnetic alloy with various technologies of preliminary processing before and after shock loading are discussed.

Abstract: The counterintuitive phenomena of elastic, perfectly plastic beam, circular plate and square plate are investigated numerically and experimentally. A new unstable slot and asymmetry of dynamic response of beam are revealed. The unsteady areas and uncertainty of response are observed numerically. At the end, the law of thermodynamics and the theorem of Lyapunov instability are employed to state the formation mechanism of counterintuitive behavior.

Abstract: Since 1975 a so-called anomalous mass-transfer in metals and alloys under pulse loading is being investigated in the Institute of Metal Physics. This phenomenon remains to be a challenge to theoreticians. Besides, one more phenomenon (observed at the same systems) was discovered – formation of metastable alloys (solutions, and, sometimes, ordered phases), with solubility limits far exceeding the equilibrium values and depending on the deformation rate. Since formation of nonequilibrium phases is also typical for alloys under irradiation, it seemed natural for us to use some of concepts and models invented in the “materials under irradiation” community. We propose 3 types of models for description of metastable solid solution formation in diffusion couple under pulse loading: 1) flux balance for both components at the interface with account of non-equilibrium defects generated during pulse loading; 2) “ballistic jump” concept, which had been invented by George Martin et al. for materials under irradiation or ball-milling, combined with another Martin’s kinetic model (1994) of diffusion; 3) modification of such a concept for the case of non-equilibrium interstitial defects. Non-equilibrium phase diagrams obtained by all 3 models are built and compared with experimental data which reflect a qualitative correspondence to one another.