Microstructural Characterization and Mechanical Properties of New Grade Al-Li Alloy

Abstract

-A new grade of Al-Li alloy, C460, was solution treated at 550°C for 3 hours, cold water quenched, and then aged at 200 o C for 24 hours. Heat treatment produced a  precipitate. In tensile and fatigue tests the precipitate was sheared by moving planar dislocation bands in response to cyclic stress strain. Results show that the  precipitate has a significant effect on the tensile and the low-cycle fatigue behavior and on the microstructural characterization. Also, the alloy appears to undergo cyclic hardening, saturation, and softening, especially at lower plastic strain amplitudes. Scanning and transmission electron microscopy revealed  precipitates and planar dislocation bands forming during plastic deformation.