Material from interrupted superplastic deformation tests of an Al-4Mg-0.3Sc alloy have been restrained in situ in the transmission electron microscope at nominally the superplastic forming temperature. In material pre-deformed to 0.2 true strain the migration of subgrain boundaries, their interaction and trapping at Al3Sc particles, and their disintegration were observed dynamically. The dislocations released during the disintegration of the subgrain boundaries moved rapidly through the matrix and were incorporated into the bounding grain boundaries. The resulting increase in grain boundary energy caused rupture and annihilation of a grain boundary triple point. This process was accompanied by a large volume rotation, resulting in a common orientation. The interaction of subgrain boundaries with Al3Sc particles, and the bypass mechanism have also been observed. These observations will be discussed in relation to the macroscopic response of the material.
Revised: March 31, 2004 |
Published: May 10, 2003
Citation
Dougherty L.M., I.M. Robertson, and J.S. Vetrano. 2003.Fundamental Processes Responsible for Continuous Dynamic Recrystallization: An In-Situ Tem Study. In Hot Deformation of Aluminum Alloys III :
2003 TMS Annual Meeting, San Diego, California, March 2-6, 2003, edited by Z. Jin, A. Beaudoin, T. A. Bieler and B. Radhakrishnan, 27-34. Warrendale, Pennsylvania:The Minerals, Metals & Materials Society. PNNL-SA-37709.