Cavitation Behavior in Superplastically Deformed Zn-22 mass%Al Alloy at Room Temperature

Abstract

The cavitation behavior in room-temperature deformation was investigated for Zn-22 mass%Al alloy by metallographical observations, and compared with that in high-temperature deformation. It was predicted from metallographical observation that the critical cavity radius of transition in growth mechanism from diffusion-controlled to plasticity-controlled would exist. In the range of plasticity-controlled growth mechanism, the cavity growth parameter, η, exhibited 1.65 and 2.45 in the deformation at high temperature and room temperature, respectively. In primary period of straining, cavities in room-temperature deformation could be nucleated more easily compared with those in high-temperature deformation. The experimental cavity growth rates in both conditions were almost same at cavity size of about 1 μm.