TWI

A coupled model, comprising a computational fluid dynamic process model, a precipitate evolution model based on classical phase transformation theory and a classical strengthening model, was formulated to investigate the effect of process parameters on microstructural and mechanical properties of welded joints fabricated by friction stir welding of initially underaged Al 7xxx series aerospace alloys. A calibration procedure was developed to determine unknown parameters in the model and was applied to AA7449 alloys. Model predictions of microstructure changes were compared with results of experiments on AA7449-TAF joints, and extended to 7050 and 7150 alloys in different weld configurations. The effects of rotational and advance speeds on weld microstructure and strength are discussed.

7th International Symposium, 20-22 May 2008, 5A: Aerospace, Paper 03