Showing 3 results for Spd
M. Kadkhodaee, H. Daneshmanesh, B. Hashemi, J. Moradgholi,
Volume 11, Issue 1 (3-2014)
Abstract
Accumulative roll-bonding process (ARB) is an important severe plastic deformation technique for production of the ultrafine grained, nanostructured and nanocomposite materials in the form of plates and sheets. In the present work, this process used for manufacturing Al/SiO 2 nanocomposites by using Aluminum 1050 alloy sheets and nano sized SiO 2 particles, at ambient temperature. After 8 cycles of ARB process, the tribological properties and wear resistance of produced nanocomposites were investigated. The wear tests by abrasion were performed in a pinon-disc tribometer. Results show that by increasing ARB cycles and the amount of nano powders, the friction coefficient of produced nanocomposites decreases.
A. Nikfahm, I. Danaee, A. Ashrafi, M. R. Toroghinejad,
Volume 11, Issue 2 (6-2014)
Abstract
In this research accumulative roll bonding process as sever plastic deformation process was applied up to
8 cycles to produce the ultrafine grain copper. Microstructure of cycle 1, cycle 4 and cycle 8 investigated by TEM
images. By analyzing TEM images the grain size measured below 100 nm in cycle 8 and it was with an average grain
size of 200 nm. Corrosion resistance of rolled copper strips in comparing with unrolled copper strip was investigated
in acidic (pH=2) 3.5 wt. % NaCl solution. Potentiodynamic polarization and EIS tests used for corrosion resistance
investigations. The corrosion morphologies analyzed by FE-SEM microscopy after polarization test and immersion for
40 hours. Results show that the corrosion resistance decreased up to cycle 2 and increased after rolled for forth time.
The corrosion degradation was more intergranular in cycle 2 and unrolled counterpart. It was more uniform rather
than intergranular type in cycle 8. Corrosion current density in unrolled sample (2.55 µAcm
-2
) was about two times of
that in cycle 8 (1.45 µAcm
-2
). The higher corrosion rate in cycle 2 in comparison with others was attributed to unstable
microstructure and increase in dislocation density whereas the uniform corrosion in cycle 8 was due to stable UFG
formation
J Gholami, M Pourbashiri, M Sedighi,
Volume 12, Issue 4 (12-2015)
Abstract
Equal-channel angular pressing (ECAP) combined with the Conform process provides a solution for the continuous production of ultrafine-grained materials. In the present study finite element method was executed to investigate the effects of die channel angle and friction on the strain homogeneity and the required torque in ECAP-Conform process. Deformation behaviour of Al 6061 wires was analyzed by using the ABAQUS/Explicit software. Finite element analyses by considering different channel angles (90ᵒ, 100ᵒ and 110ᵒ) and various friction conditions of 0.2, 0.3 and 0.4 were surveyed. The results revealed two distinct trends in which by increasing the channel angle among 90ᵒ to 110ᵒ, the amount of induced plastic strain through the wire reduced about 40%. Also required processing torque was decreased about50%. In addition more homogeneity was observed in higher angle values. The results regarding to equivalent strain, obtained from FE analyses, showed a good agreement with previous studies. Eventually plastic strains and required torque were increased about 8% and 12% when friction coefficient raised between (0.2-0.4).
