The semi-solid 2A12 aluminum alloy prepared by low voltage pulsed magnetic field process was partially remelted

and its microstructural evolution was observed by means of optical microscope and graphical analyzer. The experimental results show that the α -Al grains are coarsened gradually and become more globular with the increase of the isothermal temperature and holding time. For the 2A12 aluminum alloy

primary α -Al grains exhibit uniformly near spherical structure with size of 116

1

20 μm

and liquid phase fraction is approximately 40% at 620 ℃ for 20

4

0 min

suitable for semi-solid thixo-forming. It is found that in the early stage of the whole partial remelting process

the volume fraction of liquid is low and grains are grown up fastly mainly through crashing and fusing

while grains are grown up slowly and spheroidized mainly through elements diffusion as a result of increasing in volume fraction of liquid phase with the increase of the isothermal temperature and holding time.