Surface-layer microstructure control and bendability of a commercial purity titanium sheet using continuous cyclic bending

Abstract

Microstructural control in surface layers using continuous cyclic bending CCB and its bendability in a commercial purity titanium sheet have been investigated. The sheet of the titanium worked by CCB with little dimensional change showed 1.2 times higher hardness than that before CCB on the surface. The microstructure was controlled by CCB and the subsequent annealing for grain refinement leading to better formability in microscopic level. There was a remarkable difference in softening behavior after annealing between the samples continuous-cyclic-bent in rolling and transverse directions. This is attributable to formation of the microstructure where recrystallization does not occur easily after CCB in transverse direction. The fine grained samples showed smooth surfaces after a bending formability test, while the coarse grained one had a lot of microscopic cracks on the surface, especially for the CCB in transverse direction.

Formation of Microstructural Gradient of A2017 by RBT at Ambient Temperature

“…as described by the Hall-Petch relationship. To obtain fine grain size, several studies have been made on severe plastic deformation like ECAP (Equal-Channel-Angular-Pressing) [1][2] or CCB (Continuous-Cyclic-Bending) [3][4]. These methods are intended to impart the cumulative strain to the object by repeating the large plastic deformation.…”