Thixoforming : Semi-solid Metal Processing

Figure 9.19 (a, b) Wear appears in the form of grooves and
flattenings in the region of the oxide bag and the edges of inserts
by tilting the component when ejecting; (c) the shot chamber with
the oxide restrainer shows strong wear despite the careful coating
with mould release agents due to the duration of the temperature
influence and the movement of the shot piston.
favours deformation distortions, grooves and detachments if the component cants
insignificantly under extraction.
The bulk ceramic plates made from silicon nitride were mounted largely
unstressed. Unevenness of the metal surface, warmth delay of the holders and
thermal shock of the ceramic led, however, to failure of the plates by break. With
respect to chemical stability and resistance against abrasive wear, the silicon nitride
plates show excellent results.
The fourfold plate sample was used for secondary proof testing in other series of
experiments in which the different tool materials with coating systems were installed
Figure 9.20 Bulk ceramic insert made of silicon nitride (a) [36].
Essential difficulties affected the unstressed tailing of the ceramic
in the form in the test preparation. (b) Thermal shock of the
ceramic and also warmth delay of the steel mounts led to breaking
of the plate.
9.3 Thixocasting of Steel Alloysj331