Theory of flow localisation due to dynamic strain ageing
1988; University of Toronto Press; Volume: 36; Issue: 12 Linguagem: Inglês
10.1016/0001-6160(88)90043-0
ISSN1878-0768
Autores Tópico(s)Microstructure and Mechanical Properties of Steels
ResumoAbstract The localisation of plastic flow due to dynamic strain ageing is evaluated taking into account transient behaviour associated with the time dependence of the solute composition at mobile dislocations. A constitutive flow equation is defined which includes the local solute composition as an implicit state variable. Linear perturbation theory is employed to define an instability strain above which strain localisation occurs. The instability strain is found to be greater than the strain required for a negative steady state strain rate sensitivity of the flow stress. Both linear theory and numerical simulation show that strain localisation is characterised by sinusoidal strain and strain rate oscillations of increasing amplitude, leading to deformation band formation. The strain required for observable strain localisation is shown to depend on specimen uniformity and experimental technique. The results of the analysis are in agreement with experimental measurements in Fe-C and Au-Cu alloys.
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