Thixoforming : Semi-solid Metal Processing

206j 6 Modelling the Flow Behaviour of Semi-solid Metal Alloys
Figure 6.40 Isothermal experiment versus two-phase isothermal simulation: phase segregation.
the flow front is formed by material with a low solid content, which leads to the
observable less smooth surface of the contour.
Another important issue is solidification occurring on contact of the material
with the die walls. To investigate this phenomenon, non-isothermal experiments
and simulations are carried out. Non-isothermal experiments were carried out at a
piston velocity of 50 mm s 1 , an initial solid fraction of 52%, a material temperature
of 192 C and a die temperature of 40 C. Figure 6.41 shows the flow patterns
Figure 6.41 Flow patterns during a forming process:
(a) isothermal and (b) non-isothermal experiment.