Microstructural characteristics during hot forging of Al-Mg-Si alloy

Thermomechanical behavior of Al-Mg-Si alloys was studied to investigate the effect of microstructural features such as pre-existing substructure and distribution of particles for a successful hot forging. The controlled compression tests were carried out to find out how the alloy responds to temperature, strain amount and strain rate. Then hot forging of Al-Mg-Si alloys was carried out and analyzed by the comparison with the compression tests. Microstructural features after forging were discussed in terms of the thermomechanical response of Al-Mg-Si alloys. The deformation of Al-Mg-Si at the elevated temperature brought the recovered structure on most conditions as well reported before. However, abnormally large grains could be developed due to a specific forging conditions such as friction condition between die and forging stock, which leaded to a huge grain growth. These undesirable microstructural variations could give a rise a degradation of mechanical properties, especially fatigue strength.