Effects of thermal exposure on the mechanical properties and microstructure stability of an Al-Cu-Mg-Ag alloy

Mechanical properties and microstructural evolution of an Al-Cu-Mg-Ag alloy during thermal exposure at elevated temperature were characterized by means of tensile tests, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The tensile test results suggested that tensile strength (sigma(b)) and yield strength (sigma(s)) reduced with both increasing exposure time and temperature. Correspondingly elongation of samples increased steadily with increasing exposure time and temperature, which resulted in ductile fracture. TEM results suggested the reduction of mechanical property of samples was attributed to coarsening and reduction in amount of dominant strengthening phase-Omega phase during thermal exposure.