Solidification and microstructure modelling of welds in aluminium alloys 5754 and 6111

A solidification and microstructure modelling approach has been developed t o predict weld metal and heat affected zone (HAZ) characteristics. The free zing range and phase evolution in the weld metal region were predicted usin g thermodynamic and diffusion controlled growth calculations. The calculate d freezing range was correlated with the weld solidification cracking tende ncy. A simplified analytical model was suggested to describe thermal cycles that are experienced by the HAZ. This analytical model was coupled with a published microstructure model for age hardenable alloys to predict the har dness variations across the HAZ. The above integrated approach was evaluate d using experimental welds made on non-age hardenable 5754 (Al-Mg) and age hardenable 6111 (Al-Mg-Si) alloys using gas tungsten arc, electron beam, an d gas metal arc welding processes.