Dissipative structures in copper under impact deformation

• Published in: Physical mesomechanics Vol. 10; no. 5; pp. 275 - 280
• Main Authors: Mescheryakov, Yu.I., Zhigacheva, N.I., Divakov, A.K., Makarevich, I.P., Barakhtin, B.K.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2007
• ISSN: 1029-9599; 1990-5424
• DOI: 10.1016/j.physme.2007.11.006

Shock tests on polycrystalline copper have revealed a velocity range (400–700 m/s) in which dissipative structures of size 15 × 25 μm are formed. The structures consist of localized shear bands spaced at 100-300 nm. In the velocity range the mass velocity defect equal to the difference between the impact velocity at symmetric collision and free surface velocity corresponding to the compression pulse plateau increases sharply. Since the value of the mass velocity defect qualitatively characterizes the intensity of energy exchange between meso-and macrolevels of dynamic deformation, its growth means that the part of energy spent for structure formation increases. The transition from a uniform deformation mode to turbulent is defined by the ratio of the variation rate of mass velocity dispersion to the average mass velocity at the wave front.