Filling and solidification of A356 wheel hub were simulated by numerical simulation.According to the solidification time and temperature at different positions of the wheel hub

solidification modes of different position at the aluminum alloy hub were described

and the inhomogeneity of microstructure at the different solidification modes was described.The results reveal that the alloy is solidified in the way of layer-to-layer in the quenching zone

where grain size and microstructure exhibit homogenous

and in the zone of pressure crystallization solidification zone

the alloy is solidified in the way of simultaneous solidification

where the microstructure exhibits homogeneous distribution with round particles.In the transient zone between quenched and pressure crystallization

the alloy is solidified in the way of pastesolidification

so grain size and microstructure exhibit heterogeneous with obvious segregation of eutectic Si in the grain boundary.