1991 Volume 77 Issue 4 Pages 536-543
Densification behavior of Zn-22 mass%Al alloy powder having two different kinds of microstructures is studied by using Vacuum Hot Pressing(VHP). Sample-F is as-received powder which has fine (α+γ) microduplex structure and Sample-L, which has lamellar structure, is prepared by heating the Sample-F at 623 K for 3.6 ks followed by furnace cooling. VHP was preformed at 523 K under constant pressures from 2.5 to 100 MPa or constant cross-head speed between 0.1 to 10 min·min-1. Sample-F had a higher densification rate and a relatively higher density than Sample-L. From the VHP results, the densification maps of VHP for two samples were constructed by determing the relation between the VHP pressure and the densification rate. These maps indicated that the densification behaviors varied with microstructure of the powder. The map for Sample-F included a region having large m-value (m>0.3) while the map for Sample-L included no such a region. It was presumed that the densification process of Sample-F during VHP accelerated by superplastic VHP mechanism.
