When tested at
300 “c, the punch pressure gets large, and the head
section of the conical cup conducts local deformation
easily because of the alloy’s low yield strength and
thus it is made thinner. Finally, the fracture occurs.
Fig. 7 shows the morphology of the conical cup specimens
tested at various temperatures. At 200 and 250
“c, the large pressing depth and minimum CCV imply
good formability of the ZElO alloy sheets. A similar
phenomenon appears in the AZ31 alloy, a minimum
CCV value of 39 mm is reached at a medium temperature
of 300 “c “’].