Acoustic emission during deformation of heat treated 7075 aluminium

Abstract

Acoustic emission detected during tensile deformation of commercial grade 7075 aluminium was analysed to determine the influence of the aged (T6) and overaged (T73) tempers on emission behaviour. A comparison of acoustic emission accumulation rates as a function of strain for both tempers showed that the T6 temper had a higher rate over the strain range of 1–4%. Beyond 4% strain, the acoustic emission rates for each temper were about equal and gradually decreased up to necking. It was concluded that two separate sources were responsible for emission in the T6 temper, including dislocation shearing of GP zones and the fracture of coarse intermetallic particles. In the T73 temper, emission was attributed mainly to the fracture of coarse intermetallic particles.