摘要

After more than 80 years of practical experience and despite many noted research efforts, theories that rigorously explained the formation of the silicon eutectic phases and the modification of the morphology of those phases by specific chemical additives remained elusive. Almost all papers related to the growth and modification of silicon in casting Al-Si alloys refer to the importance of twinning and a mechanism called a twin-plane reentrant edge. However, a review paper containing detailed information on how the parallel twins are formed in a crystal during melt growth, why the twins are generated parallel to each other, what is the prerequisite for growing a facetted dendrite, and how effective are various rare earth elements is missing in the literature. A comprehensive review is conducted on the models proposed for the flaky silicon growth including twin-plane reentrant edge and the models proposed for eutectic modification: impurity induced twinning and restricted growth theory. Furthermore, the papers with focus on modifying efficiency of the rare-earth metals have been reviewed.

  • 出版日期2014-5