This paper presents some experimental results on the effect of the notch–depth ratio on intermittent electromagnetic radiation during the progressive plastic deformation of a Cu-Ni alloy sheet specimen under tension. An electromagnetic antenna was used for receiving the electromagnetic waves emitted by the deforming specimen. The specimens (with varied notch-depth ratios) first emit electromagnetic radiation near yield which is always oscillatory in nature. However, the axial strain at the initial emission of the electromagnetic radiation increases with an increase in the notch-depth ratio. The nature of electromagnetic radiation signals changes from oscillatory to exponential until instability is reached. This shows that the viscous coefficient of the material of the specimens increases during strain-hardening. The paper also presents a correlation between electromagnetic radiation emission parameters and the radius of the plastic zone created ahead of the advancing crack tip, an important parameter in fracture mechanics. With an increase in the plastic zone size, the amount of intermittent electromagnetic radiation decreases asymptotically: the first electromagnetic radiation amplitude increases linearly and a maximum energy burst first decreases the electromagnetic radiation frequency parabolically. Initial electromagnetic radiation characteristics differ considerably from optimum electromagnetic radiation emissions within the strain-hardening region. These experimental results show a novel technique for studying various fracture mechanics parameters and also for developing a non-contact crack growth monitor.

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This paper presents experimental results on intermittent electromagnetic radiation during plastic deformation of Cu -Nialloys under tension and compression modes of deformation. On the basis of the nature of electromagnetic radiation signals, oscillatory or exponential, results show that the compression increases the viscous coefficient of Cu -Ni alloys duringp lastic deformation. Increasingt he percentage of solute atoms in Cu -Nialloys makes electromagnetic radiation strength higher under tension. The electromagnetic radiation emission occurs at smaller strains under compression showing early onset of plasticd eformation. This is attributed to the role of high corer egion tensile residual stresses in the rolled Cu -Nialloy specimensinaccordancew itht he Bauschinger effect. The distance between the apexes of the dead metalcones duringcompression playsas ignificant role in electromagnetic radiation parameters. The dissociation of edge dislocations into partials and increase in internal stresseswith increase in solute percentage in Cu -Nia lloys under compression considerably influences the electromagnetic radiation frequency.R. Singh et al.: Correlation of deformation induced electromagnetic radiation with mechanical properties of Cu -Nialloys Int.

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