The semisolid slurry of AlSi7Mg alloy was prepared by being poured at a low superheat and stirred by an electromagnetic field at a low power for a short time

and then the slurry was further soaked for proper time and finally rheoformed into a key-shaped die cavityin this paper.The influence of slurry temperature

specific pressure and injection speed on the rheoforming process was also studied.The experimental results show that if the melt of AlSi7Mg alloy is poured at 630 ℃ or 650 ℃and meanwhile stirred by an electromagnetic field at a low power for a short time

the most primary α-Algrains solidified in the slurry are spherical and only a few are rosette-like.If the slurry is then homogeneously soaked in the liquidus-solidus range for some time

the ripening of primary α-Alis developed further and it becomes more spherical and larger.The experimental results also show that the slurry temperature

injection pressure and speed have great influence on the filling ability.The higher the slurry temperature

injection pressure and speed

the higher the slurry filling ability

and the shorter the core distance from the ingate

the more easily the die cavity is filled.With the given key-shaped casting

if only the slurry temperature should be equal to or more than 585 ℃

or the injection pressure is equal to or more than 20 MPa

or the injection speed should be equal to or more than 1.73 m/s

the key-shaped die cavity can be filled completely.The microstructuraldistribution in the casting is very homogeneous and it shows that the slurry prepared by above-mentioned method is very suitable for rheoforming and helpful to obtaining high quality castings.