Localized deformation bands in Portevin–LeChâtelier plastic instabilities at a constant stress rate

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 279; no. 1; pp. 179 - 184
• Main Authors: Kovács, Zs, Lendvai, J, Vörös, G
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 29.02.2000; Elsevier
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Deformation and plasticity (including yield, ductility, and superplasticity); Exact sciences and technology; Irregular instability steps; Localized deformation bands; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Metals. Metallurgy; Physics; Portevin–Le Châtelier effect; Localized deformation bands; Portevin–Le Châtelier effect; Irregular instability steps; Deformation band; Aluminium base alloys; Portevin-Le Chatelier effect; Magnesium alloys; Strain aging; Tensile tests; Plasticity; Instability; Experimental study; Localization; Stress-strain relations; Strain rate
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/S0921-5093(99)00628-0

Portevin–Le Châtelier (PLC) plastic instabilities were examined in constant loading rate tensile tests. Irregular instability steps were observed in an intermediate stress rate region on the stress versus strain curves. The irregular steps are caused by the repeated activation of localized high deformation bands. The activation of the localized bands shows some regularity. The origin of the irregular instability steps goes back to the initialization of the first band at the onset point of the instabilities. It is argued that the appearance of irregular instability steps at low strain rates is related to the decrease of the depth of the dynamic strain aging toward small strains.