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Abstract: The influence of abrupt shearing on transient rheological
behavior of semi-solid A356 alloy with different morphology of primary
α-phases is explored through the use of rest time experiment by a
self-designed rheometer. The morphology of primary α-phases is
degenerated dendrites prepared via isothermal mechanical stirring at
141.8 s–1. Results indicate that the primaryα-phases are gradually
degenerated under isothermal shearing, as a result, the apparent
viscosity of semisolid A356 alloy is gradually reduce to a equilibrium
state. Empirical transient rheological equations are then obtained by
ways of curves fitting. The relation between parameters of the empirical
equation and morphology of primaryα-phases of semisolid alloy is also
gained by means of regression analysis. Results also show that the
semisolid A356 alloy exhibited more notable shear thinning or
pseudoplastic behavior, and expressed more prominent behavior of time
dependence along with the degeneration of primary α-phases of the
semisolid alloy, in other words, the semisolid alloy is possessed by
obvious thixotropic behavior.
Key words: Semi-solid alloy Rheological behavior Apparent
viscosity A356 alloy
CLC No: TG146.2
TG115.9
中国博士后基金资助项目(200031). Received 20010122, received in revised form
20011016
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