Due to the characteristics of semi-solid slurry, semi-solid forming has the following natural advantages over other casting methods
(1) In traditional liquid die casting, due to the low viscosity of liquid slurry, the flow front is easy to lose stability in the filling process, which leads to the flow phenomena such as entrainment and convection. These flow phenomena can greatly increase the fluidity defects caused by slurry flow, such as air entrainment. The semi-solid slurry has a certain viscosity, and the flow front is relatively stable during the flow, and the flow front is nearly linear stable filling. The semi-solid forming can effectively avoid the flow defects caused by the flow front instability.
(2) Due to the large volume shrinkage in the solidification process of traditional liquid die casting, it is easy to produce shrinkage cavity and porosity due to shrinkage. In the semi-solid forming process, the shrinkage is smaller due to the low liquid fraction of the slurry. In addition, the feeding measures in the die casting process can effectively avoid the shrinkage cavity and porosity caused by solidification shrinkage.
(3) Compared with the traditional liquid die casting, the porosity content of semi-solid die-casting products is lower or even without pores. On this basis, semi-solid die-casting products can be strengthened by heat treatment to improve their mechanical properties.