Effect of Aging Treatment on Microstructure and Mechanical Properties of Tig Welded Joints of 2195-T8 Al-Li Alloy

The weld joint of 2195-T8 Al-Li alloy was fabricated by tungsten inert gas welding and subsequently subjected to solution plus single and double aging treatments. The microstructure and properties were analyzed. The results showed that the aging treatment didn't significantly change the average grain size. The phases of δ΄/β΄and θ΄ distribute in weld zone (WZ) region and θ΄ phase distribute in heat affected zone (HAZ) and BM regions after single aging treatment. After double aging treatment, the precipitates in WZ was coarse δ΄/β΄and θ΄ phases, while T1 phase and σ phase appear in HAZ and base metal (BM) regions. Compared to the single aging treatment, the tensile strength of the weld increased from 465 MPa to 515 MPa, while the elongation decreased from 22% to 9% after double aging treatment which can be attributed to the variation of the precipitates.