TY - JOUR
T1 - Microstructure evolution of 6061 O Al alloy during ultrasonic consolidation
T2 - An insight from electron backscatter diffraction
AU - Mariani, E.
AU - Ghassemieh, E.
PY - 2010/4/1
Y1 - 2010/4/1
N2 - 6061 O Al alloy foils were welded to form monolithic and SiC fibre-embedded samples using the ultrasonic consolidation (UC) process. Contact pressures of 135, 155 and 175 MPa were investigated at 20 kHz frequency, 50% of the oscillation amplitude, 34.5 mm s sonotrode velocity and 20 °C. Deformed microstructures were analysed using electron backscatter diffraction (EBSD). At all contact pressures deformation occurs by non-steady state dislocation glide. Dynamic recovery is active in the upper and lower foils. Friction at the welding interface, instantaneous internal temperatures (0.5-0.8 of the melting temperature, T), contact pressure and fast strain rates result in transient microstructures and grain size reduction by continuous dynamic recrystallization (CDRX) within the bonding zone. Bonding occurs by local grain boundary migration, which allows diffusion and atom interlocking across the contact between two clean surfaces. Textures weaken with increasing contact pressure due to increased strain hardening and different grain rotation rates. High contact pressures enhance dynamic recovery and CDRX. Deformation around the fibre is intense within 50 μm and extends to 450 μm from it.
AB - 6061 O Al alloy foils were welded to form monolithic and SiC fibre-embedded samples using the ultrasonic consolidation (UC) process. Contact pressures of 135, 155 and 175 MPa were investigated at 20 kHz frequency, 50% of the oscillation amplitude, 34.5 mm s sonotrode velocity and 20 °C. Deformed microstructures were analysed using electron backscatter diffraction (EBSD). At all contact pressures deformation occurs by non-steady state dislocation glide. Dynamic recovery is active in the upper and lower foils. Friction at the welding interface, instantaneous internal temperatures (0.5-0.8 of the melting temperature, T), contact pressure and fast strain rates result in transient microstructures and grain size reduction by continuous dynamic recrystallization (CDRX) within the bonding zone. Bonding occurs by local grain boundary migration, which allows diffusion and atom interlocking across the contact between two clean surfaces. Textures weaken with increasing contact pressure due to increased strain hardening and different grain rotation rates. High contact pressures enhance dynamic recovery and CDRX. Deformation around the fibre is intense within 50 μm and extends to 450 μm from it.
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-77249156385&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2009.12.035
DO - 10.1016/j.actamat.2009.12.035
M3 - Article
AN - SCOPUS:77249156385
VL - 58
SP - 2492
EP - 2503
JO - Acta Materialia
JF - Acta Materialia
SN - 1359-6454
IS - 7
ER -