ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
The study on new rheoforming technologies of semisolid alloys has recently been onemain subject interesting many professors, experts and industrials, and so many new methods aboutpreparing semisolid alloy slurry and rheoforming process have been put forward. The semisolidslurry of AlSi7Mg alloy was prepared by being poured at a low superheat and stirred by anelectromagnetic field at a low power for a short time, and then the slurry was further soaked forproper time and finally rheoformed into a key-shaped die cavity in this paper. The influence ofslurry temperature, injection specific pressure and injection speed on the rheoforming process wasalso studied. The experimental results show that if AlSi7Mg alloy melt is poured at 630°C or 650°Cand meanwhile stirred by an electromagnetic field at a low power for a short time, the most primaryα-Al grains solidified in the slurry are spherical and only a few are rosette-like. If the slurry aftermade is then soaked in the liquidus-solidus range for some time, the ripening of primary α-Algrains is developed further and they become more spherical and larger. The experimental resultsalso show that the slurry temperature, injection pressure and speed have a great influence on fillingability. The higher the slurry temperature, injection pressure and speed, the higher the slurry fillingability, 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 than585,, or the injection pressure is equal to or more than 20 MPa, or the injection speed should beequal to or more than 1.73m/s, the key-shaped die cavity can be filled completely. Themicrostructural distribution in the casting is very homogeneous and it shows that the slurry preparedby the new method is very suitable for rheoforming and helpful to obtaining high quality castings
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/22/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.116-117.410.pdf
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