TY - JOUR
T1 - Local changes in the microstructure, mechanical and electrochemical properties of friction stir welded joints from aluminium of varying grain size
AU - Orłowska, Marta
AU - Pixner, Florian
AU - Hütter, Andreas
AU - Kooijman, Agnieszka
AU - Jasiński, Cezary
AU - Gonzalez-Garcia, Yaiza
AU - Enzinger, Norbert
AU - Lewandowska, Małgorzata
PY - 2021
Y1 - 2021
N2 - The present study shows results of friction stir welded (FSW) samples after different plastic deformation routes. The welds were made of coarse-grained and ultrafine-grained commercially pure aluminium. As a plastic deformation method a new hybrid process has been chosen, which resulted in obtaining samples with different characteristics of microstructure, which also differed in dependance of the examined plane. Microstructure observations showed that, regardless of the base material, due to continuous dynamic recrystallization a stir zone was characterized by equiaxial grains with an average size of 3.5–5.0 μm. However, significant differences in the changes of the microstructure in thermomechanically affected and heat affected zones have been obtained between welds. Microhardness profiles revealed a decrease in the stir zones in comparison with the initially deformed samples, but an increase for the annealed samples. Tensile tests showed differences between the samples. In the deformed samples, the rupture occurred in a stir zone, while in the undeformed samples in the base material. In addition, due to the application of 3D digital image correlation, it was possible to observe deformation and local changes between the weld zones during the tensile test. Additionally, local electrochemical measurements were performed with two sizes of working electrode, which included the application of microcapillary technique. The results showed higher corrosion resistance in 3.5% NaCl in the stir zones.
AB - The present study shows results of friction stir welded (FSW) samples after different plastic deformation routes. The welds were made of coarse-grained and ultrafine-grained commercially pure aluminium. As a plastic deformation method a new hybrid process has been chosen, which resulted in obtaining samples with different characteristics of microstructure, which also differed in dependance of the examined plane. Microstructure observations showed that, regardless of the base material, due to continuous dynamic recrystallization a stir zone was characterized by equiaxial grains with an average size of 3.5–5.0 μm. However, significant differences in the changes of the microstructure in thermomechanically affected and heat affected zones have been obtained between welds. Microhardness profiles revealed a decrease in the stir zones in comparison with the initially deformed samples, but an increase for the annealed samples. Tensile tests showed differences between the samples. In the deformed samples, the rupture occurred in a stir zone, while in the undeformed samples in the base material. In addition, due to the application of 3D digital image correlation, it was possible to observe deformation and local changes between the weld zones during the tensile test. Additionally, local electrochemical measurements were performed with two sizes of working electrode, which included the application of microcapillary technique. The results showed higher corrosion resistance in 3.5% NaCl in the stir zones.
KW - Aluminium
KW - Friction stir welding
KW - Local characterization
KW - Mechanical properties
KW - Microcapillary
KW - Ultrafine-grained microstructure
UR - http://www.scopus.com/inward/record.url?scp=85119902949&partnerID=8YFLogxK
U2 - 10.1016/j.jmrt.2021.11.057
DO - 10.1016/j.jmrt.2021.11.057
M3 - Article
AN - SCOPUS:85119902949
SN - 2238-7854
VL - 15
SP - 5968
EP - 5987
JO - Journal of Materials Research and Technology
JF - Journal of Materials Research and Technology
ER -