ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Solidification behaviour of 357 Al-alloy under intensive forced convection in the rheo-die-casting(RDC) process, was investigated experimentally to understand the effects of the intensity of forcedconvection and shearing time on the nucleation and growth behaviour. It was found that underintensive forced convection, heterogeneous nucleation occurred continuously throughout the entirevolume of the solidifying melt. All the nuclei could survive due to the uniform temperature andcomposition fields created by the forced convection. This has been named as ‘effective andcontinuous nucleation’. It is also found that the nuclei grow spherically with an extremely fastgrowth rate. This makes the primary solidification essentially a slow coarsening process, in whichOstwald ripening takes place by dissolution of the smaller particles. In addition, it was found thatintensive forced convection suppresses partially the formation of the primary phase, promotenucleation of the primary particles, and hinders the particle growth
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.519-521.1747.pdf
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