Microstructural evolution and mechanical properties of high purity aluminium processed by equal-channel angular pressing

0377776 - ÚFM 2013 RIV JP eng J - Journal Article
Dvořák, Jiří - Sklenička, Václav - Horita, Z.
Microstructural evolution and mechanical properties of high purity aluminium processed by equal-channel angular pressing.
Materials Transactions. Roč. 49, č. 1 (2008), s. 15-19. ISSN 1345-9678. E-ISSN 1347-5320
Institutional research plan: CEZ:AV0Z20410507
Keywords : pure aluminium * equal-channel angular pressing (ECAP) * tensile property * strain rates * grain refinement * stacking fault energy
Subject RIV: JJ - Other Materials
Impact factor: 0.753, year: 2008

High purity (99.999%) Al was subjected to ECAP for up to 8 passes through route BC. Hardness measurements and tensile tests were conducted at room temperature with respect to the number of ECAP passes. It is shown that the hardness and the tensile strength increased to take a maximum at 2 passes. However, unusual behaviour was observed such that further straining by ECAP for more than 2 passes decreased the hardness and tensile strength. Microstructural observation revealed that straining by ECAP for 2 passes led to the development of a subgrain structure having dislocations within some subgrains and tangled dislocations near subgrain boundaries. After 8 passes, the grains became larger and the grain boundaries sharpened and clearly defined. It is considered that the high dislocation mobility arising from high stacking fault energy and very low level of impurities were responsible for the unusual tensile behaviour and the difficulty in reducing the grain size.
Permanent Link: http://hdl.handle.net/11104/0209846