This paper established the thermal field model and phase transformation model for near-liquidus casting process. The solid fraction was used to couple the macroscale and mesoscale calculations. The evolution of the morphology of primary phase of 6061 alloys was simulated and experimentally studied under different conditions

e.g. pouring temperature

casting velocity

cooling intensity etc. The results show that the pouring temperature has the largest effect on the morphology of primary phase. When isothermally holding a while and then pouring near the liquidus

the morphology of primary phase is ideal globular. It is shown that the desired semisolid structure of 6061 alloy can be obtained under the conditions of 940K pouring temperature

0.05 m3/min cooling intensity and 0.002 m/s casting velocity.