Effect of strain rate on acoustic emission during tensile deformation of alpha-brass

Abstract

In the present investigation, acoustic emission (AE) technique has been used to study the effect of variation in strain rate on AE signals during tensile deformation of alpha-brass. Tensile tests have been carried out at four different strain rates, i.e. 3.33 x 10(-4), 6.66 x 10(-4), 1.33 x 10(-3) and 2 x 10(-3) s(-1) with simultaneous monitoring of AE parameters. Results indicated that the intensity of AE signals increased with increase in strain rate, which had been attributed to the combined effect of dislocation motion and twinning. Optical microscopy results of deformed samples showed an increase in twin density, i.e. the number of twins per unit area with that of strain rate, which had a profound effect on AE cumulative counts. The fracture surface analysis of deformed sample by field emission scanning electron microscopy showed a transition from ductile to brittle behaviour with increase in the value of strain rate.