Characterisation of PLC band parameters using laser speckle technique

A newly developed laser speckle technique was used in situ during tensile testing to directly observe PLC bands. Some of the observations are quite different from those hitherto reported. Effect of strain, strain rate, specimen thickness and ageing on band width, band velocity and band angle was studied. All the trends are in accordance with previous studies except that band width is found to increase with strain and reach a plateau. The effect of ageing temperature and time on band parameters is reported for the first time. It is found that different types of precipitates obtained at different ageing temperatures affect PLC band behaviour in somewhat different manner.