|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Ultrafine Grained Materials IX
||Development of Dislocation Structures in Hydrostatically Extruded Pure Aluminium
||Witold Chrominski, Malgorzata Lewandowska
|On-Site Speaker (Planned)
Hydrostatic extrusion with a total true strain of 1.8 was applied to pure aluminium, which resulted in a non-homogenous structure with two types of grains: <111> oriented which are significantly refined with the size of 500 nm and <001> oriented which are relatively large with well developed dislocation substructure. Diffraction contrast experiment showed that three types of dislocations arrangements form in the <001> grains. Two of them were recognized as low energy dislocation structure (LEDS) – screw dislocation square twist network and dislocation walls containing dislocations with at least four different Burgers vectors. Third structure was a single Burgers vector dislocation array. In-situ straining experiment showed that LEDS are stable and do not change during plastic deformation whereas non-LEDS are unstable and gliding dislocation interact with them. For low strain, these structures collapse whereas for higher strain, such a structure is a nuclei for LEDS due to efficient dislocation intersections.