Analysis of the formation of sub-grain boundaries in commercially pure titanium compressed at elevated temperature

Abstract

This work mainly studies the dislocation configurations and grain boundaries in the commercially pure titanium compressed at high temperature by transmission electron microscopy. Examination of the microstructures indicated that the boundaries constructed in this work can be divided into two types: (1) formed from the stacking faults and dislocations, in the minority; (2) formed from the dislocations alone, in the majority. It was found that dislocations was largely produced from the intragranular and the pre-existing grain boundaries during hot compression test, and the formation of new grain boundaries were stem from the piles up of dislocations. Meanwhile, the formation process of the boundary accumulated from dislocations was observed for the first time. In addition, the misorientation between sub-grain and adjacent grain verifies the motion of dislocations causes the rotation of the sub-grain in nominal.