Effect of specimen condition, orientation and alloy composition on PLC band parameters

The PLC band parameters are studied in an AA2219 aluminium alloy using a newly developed laser speckle technique for the direct observation of PLC bands. It is observed that though the magnitude of serration is larger in the solution treated condition, the PLC bands are brighter and sharper in the as-received condition. The band multiplicity is much greater, and band width and band velocity are much lower in the as-received condition as compared to the solution-treated condition. Band angle is not affected by the specimen condition. The specimen orientation, on the other hand, does not make much difference in the mechanical properties, serration characteristics and PLC band parameters of the AA2219 alloy tested in the solution-treated condition. The serration characteristics and PLC band behaviour are also found to be similar in the AA5082, AA7020 and AA2219 alloys tested in the solution-treated condition. These various effects are explained by solute content and microstructure of the material.