한국주조공학회

In the present study the effect of cooling rate during solidification on the microstructural characteristics of Al-xAg (x = 31, 33, 35 at.%) in-situ binary eutectic composites has been investigated. To provide a wide range of cooling rate three different casting techniques, i.e. conventional casting, injection casting, and melt spinning have been used. The observed microstructure is very much dependent on the cooling rate. The fcc α-Al and hcp Ag2Al phases exhibits an orientation of (111)Al//(0001)Ag2Al, [1- 10]Al//[11-20]Ag2Al. The microstructure of the melt-spun samples contains Widmanstätten structure resulting from solid-state transformation and nano scale two-phase structure resulting from solid-state phase separation. The microstructure of injection- cast samples contains eutectic structure and solid state phase-separated structure. On the other hand, conventional-cast samples exhibit a microstructure consisted of plate-type eutectic structure.

Al-Ag2Al eutectic, Eutectic alloy, In-situ eutectic composite, Phase transformation.