| Title |
Superplastic Deformation Behavior of a Zn-0.3 wt.% Al Alloy |
| Authors |
하태권(Tae Kwon Ha) ; 손중락(Jung Rak Son) ; 장영원(Young Won Chang) |
| Abstract |
The superplastic deformation behavior of a Zn-0.3wt.%Al alloy has been investigated in this study, by employing a new thermomechanical treatment (TMT) process. The TMT process employed appears to produce a fine and equiaxed grain structure that is very stable exhibiting no further grain growth. A remarkable tensile elongation of nearly 1400% has been obtained at room temperature for a Zn-0.3 wt.%Al alloy with the average grain size of 1 ㎛. This elongation seems to be the largest reported so far in the open literatures for dilute Zn-Al alloys. Room-temperature superplasticity is very benificial for the direct investigation of superplastic deformation mechanisms by using in-situ TEM and SEM studies without severe experimental constraints. While the room-temperature superplasticity has been observed in several microduplex superplastic materials, only a few investigations have been reported for single phase alloys so far. Using the superplastic material obtained in this study, a more systematic study on the physicsal mechanisms of superplastic deformation in single-phase alloys appear to be possible through an in-situ TEM or SEM observation. The major deformation mechanism was found to be the grain boundary sliding for this alloy as reported for other single phase alloys. The strain rate sensitivity parameter of a specimen with 1 ㎛ grain size showed a somewhat lower value of 0.41 considering the large elongation of 1400%. |