Acoustic emission generated during tensile testing of 2024 aluminum alloys

Abstract

Tension tests of 2024 aluminum alloys solution treated at 500°C for 8hr, quenched and subsequently aged at room temperature in the range of aging time from 10 to 10₄min were carried out at the cross head speed 1mm/min. Average AE voltage-strain curves show the 1st peak at the strain near 0.2% proof stress and the 2nd peak in the strain region about 5 to 10%. The 1st peak voltage lowers as the aging time is prolonged. The 2nd peak is nearly constant regardless of aging time. A sensor of 450kHz frequency indicates lower values of the 1st peak than that of 140kHz, but these two sensors indicate nearly the same values of the 2nd peak. The change of rate count during plastic deformation well corresponds to that of average voltage. The total AE count decreases as the aging time is prolonged.