M. Xiong et Av. Kuznetsov, An investigation of the microporosity formation in an Al-4.1% Cu alloy casting in microgravity and in standard gravity, HEAT MASS T, 38(1-2), 2001, pp. 35-43
The microporosity formation in a vertical unidirectionally solidifying Al-4
.1%Cu alloy casting is modeled in both microgravity and standard gravity as
well as in the conditions of decreased (Moon, Mars) and increased (Jupiter
) gravity. Due to the unique opportunities offered by a low-gravity environ
ment (absence of metallostatic pressure and of natural convection in the so
lidifying alloy) future microgravity experiments will significantly contrib
ute to attaining a better physical understanding of the mechanisms of micro
porosity formation. One of the aims of the present theoretical investigatio
n is to predict what microporosity patterns will took like in microgravity
in order to help plan a future microgravity experiment. To perform these si
mulations, the authors suggest a novel three-phase model of solidification
that accounts for the solid, liquid, and gas phases in the mushy zone. This
model accounts for heat transfer, fluid flow, macrosegregation, and microp
orosity formation in the solidifying alloy. Special attention is given to t
he investigation of the influence of microporosity formation on the inverse
segregation. Parametric analyses for different initial hydrogen concentrat
ions and different gravity conditions are carried out.