Microstructure and Mechanical Properties of 2219-T Aluminum Alloy Welded by Friction Stir Welding

Friction stir welding technology as the research object was discussed in detail about microstructure, mechanical properties, fracture morphology and other characteristics through the combination of experiment and theoretical analyses. The purpose of this study was to analyze the characteristics of aluminum alloy, find the weaken reasons of welded joints and put forward the appropriate method of solution heat treatment. The results show that the average tensile strength of the joints was changed from 400 MPa to 300 MPa and then to 380 MPa along with the process of welding and post welding heat treatment, and the elongation was increased or decreased from 10% to 8% and then to 3% as well. Through the recrystallization heat treatment technology with high temperature oscillating to hold the fine grain at short time, the ductility of welded joints can be restored and softening problem of joints can be eliminated.