associated with pure metals and eutectic alloys, wherein solid-ification takes place by the advance of plane interface from the
mold wall with the metal flow continuing until the channel is
finally choked (Fig. 10(a)). On the other hand, in alloys, constitu-tional undercooling and other phenomena produce independent
crystallization in main liquid mass, leading to the presence of
free crystals in the liquid, which can arrest the flow and hence
reduce the fluidity (Fig. 10(b)). Further, the hindrance caused
by crystals with irregular growth surfaces in long freezing range
alloys is much greater than that of comparatively smooth crystal-lization interface front of pure metals and eutectic alloys. Thus,
fluidity values of pure metals and eutectic alloys are greater
than those of alloys solidifying over a temperature range. This
is the reason for the wide practical preference for eutectic or
near eutectic alloys for foundry purposes, particularly for cast-ing with thin sections.
associated with pure metals and eutectic alloys, wherein solid-ification takes place by the advance of plane interface from themold wall with the metal flow continuing until the channel isfinally choked (Fig. 10(a)). On the other hand, in alloys, constitu-tional undercooling and other phenomena produce independentcrystallization in main liquid mass, leading to the presence offree crystals in the liquid, which can arrest the flow and hencereduce the fluidity (Fig. 10(b)). Further, the hindrance causedby crystals with irregular growth surfaces in long freezing rangealloys is much greater than that of comparatively smooth crystal-lization interface front of pure metals and eutectic alloys. Thus,fluidity values of pure metals and eutectic alloys are greaterthan those of alloys solidifying over a temperature range. Thisis the reason for the wide practical preference for eutectic ornear eutectic alloys for foundry purposes, particularly for cast-ing with thin sections.
การแปล กรุณารอสักครู่..