Solidified structure of Mg97Y2Cu1 alloy reinforced by long period ordered structure was investigated comparatively without treatment

with DC magnetic field（DCMF）treatment

pulsed magnetic field（PMF）treatment and compound treatment of DCMF with PMF.Grain size of the alloy at different pulsed magnetic field strength

pulse frequency

mold temperature and pouring temperature under the conditions of compound magnetic field was investigated.The results show that solidified structure of the alloy can be improved significantly by compound magnetic field.The improvement effect by compound treatment is more efficient than by DCMF treatment or PMF treatment.Primary phase of the alloy is changed into fine equiaxed grains or rosette crystals with more uniform and continuous distribution of second phase and increases of its volume fraction.When pulsed magnetic field strength is at 0

0

.25 T or pulse frequency is at 1

1

0Hz

grain size of the alloy is decreased gradually with the increase of pulsed magnetic field strength or pulse frequency.When mold temperature is at 20

6

00℃

with the increase of mold temperature

grain size of the alloy is decreased firstly and then increased.When pouring temperature is at 650

7

50℃

with the increase of pouring temperature

grain size of the alloy is increased firstly and then decreased.