Micropore Evolution and Damage Behavior of Rapid-Solidified Al-Zn-Mg-Cu Alloy during Hot Plastic Forming

Rapid-solidified Al-Zn-Mg-Cu alloys possess widespread application prospects owing to their excellent properties, particularly high specific strength. Nevertheless, their further development for use as advanced structural parts is significantly limited by their intrinsic porosity. Herein, the flow stress subroutine and micropore evolution model are combined to predict the cracking and damage behavior of a rapidly solidified Al-Zn-Mg-Cu disk-shaped part during hot forging. The results reveal that the damage to the part during plastic forming is inversely proportional to the relative density. Reasonable matching between the height-to-diameter ratio (H/D) and the initial relative density is the key factor in avoiding cracking and damage to the part. The closure sequence of the micropores is from the center to the outside of the billet. A billet with an H/D of 1 and initial relative density of 0.95 can reach full density after forming, and a damage-free part can be obtained. These simulation results are verified by analyzing the microstructural characteristics and mechanical properties of the actual forged part.

Automated summary

Rapid-solidified Al-Zn-Mg-Cu alloys show great potential for various applications due to their excellent properties, especially high specific strength. However, their use as advanced structural parts is limited by their intrinsic porosity. In this study, a flow stress subroutine and micropore evolution model were combined to predict the cracking and damage behavior of a rapidly solidified Al-Zn-Mg-Cu disk-shaped part during hot forging. The results showed that the damage to the part during plastic forming is inversely proportional to the relative density. A reasonable matching between the height-to-diameter ratio (H/D) and initial relative density is crucial to avoid cracking and damage. The closure sequence of the micropores was observed from the center to the outside of the billet. It was found that a billet with an H/D of 1 and initial relative density of 0.95 can achieve full density after forming, resulting in a damage-free part. These simulation results were confirmed by analyzing the microstructural characteristics and mechanical properties of the actual forged part.