High pressure die casting of aluminum alloys: A fluidity-centric review

Fluidity is one of the critical indicators for evaluating castability and has become a major research focus over the past five years due to advancements in high pressure die casting (HPDC) technology. Aluminum alloys, which were widely used in HPDC, offer promising structural and functional properties. The variables affecting the fluidity of alloy determine the solidification mode and the behavior of liquid flow, which forms the fundamental basis for understanding and controlling the macroscopic flow length. Here, an up-to-date and comprehensive review of research on fluidity of HPDC aluminum alloys is provided. It begins by discussing the main variables affecting fluidity, such as shot phases, compositions, solidification mode, and flow regime transition. The discussion then presents a summary of the recently proposed flow choking mechanisms. Additionally, algorithms related to fluidity under HPDC are reviewed, with particular emphasis on the increasing application of machine learning techniques in recent years. Finally, remaining challenges and perspectives for future materials, processes, and applications in HPDC fluidity research are proposed.