ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
In this work, effective parameters of SIMA process to obtain non dendriticmicrostructure in A356 alloy were investigated. In addition, the effect of SIMA process on theevolution of morphology of silicon and intermetallic phases in this alloy was studied.Microstructure images obtained from optical microscopy and SEM observation showed thatincrease in plastic work up to 40% and then holding of samples in the semi solid state attemperature of 580oC, causes that primary dendritic structure changes to non dendritic, fine andglobular structure, but optimum reheating time completely depended on initial thickness of samples.If all parameters of SIMA process are the same, the grain boundaries of thinner samples begin towet and following globalization will be completed in shorter reheating time rather than thicker ones.Moreover, it was found that the intermetallic phases lost their angular or needle morphology andgradually changed to rounded morphology and even to globular form. Also the optimum reheatingtime thoroughly depends on primary casting microstructure as the finer casting microstructure beginto globalize faster than thicker one under more little stains
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.141-143.367.pdf
