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

and then the slurry was further soaked for proper time and finally rehoformed into a key-shaped die cavity.The influences of slurry temperature

injection specific pressure and injection rate on the rheoforming process were investigated.The results show that the major spherical primary α-Al phase and a little rosette-like primary phase in the AlSi7Mg alloy can be observed with pouring at 630～650 ℃ and stirring by an a low power electromagnetic field for a short time.The primary α-Al phase can be further spheroidized and coarsened as a result of accelerate ripening of primary α-Al phase by soaking treatment at liquid-solid zone for some time.The experimental results reveal that the slurry temperature

injection specific pressure and injection rate have great effects on the filling ability of semi-solid AlSi7Mg slurry

where the higher the slurry temperature

injection specific pressure and injection rate are

the higher the slurry filling ability and the shorter the core distance for the ingate are and the easier the filling of semi-solid AlSi7Mg alloy is.The slurry can fully fill the cavity of key parts with the slurry temperature more than 585 ℃

or the injection specific pressure more than 20 MPa

or the injection rate more than 1.73 m/s.The key parts have uniformly distributed microstructures

showing that the above-mentioned methods can be suitable for producing the semi-solid parts with high quality.