Showing 4 results for Fine Grain
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
A. Eivani, S.h. Seyedein, M. Aboutalebi,
Volume 15, Issue 1 (3-2018)
Abstract
In this research, samples of AlMg0.7Si aluminum alloy are deformed up to three passes using equal channel angular pressing (ECAP). Formation of a sub-micron structure after three passes of ECAP is demonstrated. Microstructural stability of the samples is investigated at temperatures of 300-500 °C. At 300 °C, fine recrystallized structure forms after 10 min which remains stable when the annealing proceeds up to 18 hrs. However, at 350 °C and higher, the microstructure is quite unstable. Even by 10 sec annealing, the samples exhibit recrystallized structure which turned to abnormal grain growth when temperature enhances to 500 °C and time up to 300 sec.
H. Jafarian, H. Miyamoto,
Volume 17, Issue 1 (3-2020)
Abstract
In the present work, accumulative roll bonding (ARB) was used as an effective method for processed of nano/ultrafine grained AA6063 alloy. Microstructural characteristics indicate considerable
grain refinement leading to an average grain size of less than 200 nm after 7 ARB cycles. Texture analysis showed that 1-cycle ARB formed a strong texture near Copper component ({112}<111>). However, texture transition appeared by increasing the number of ARB cycles and after 7-cycle of ARB, the texture was mainly developed close to Rotated Cube component ({100}<110>). The results originated from mechanical properties indicated a substantial increment in strength and microhardness besides a meaningful drop of ductility after 7 ARB cycles.
Gajanan M Naik, Santhosh Kumar B M, Shivakumar M M, Ramesh S, Maruthi Prashanth B H, Gajanan Anne6,
Volume 22, Issue 3 (9-2025)
Abstract
Magnesium and the alloys made from the same metal are utilized in the engineering applications such as automotive, marine, and aircraft, among others due to high strength to weight. Nevertheless, the applications of magnesium alloys are currently limited to a certain level due to their poor wear and corrosion properties. Another effective strategy for enhancing these properties involves utilizing the process of equal channel angular extrusion (ECAE), which serves to refine the grain structure, thereby resulting in improved material properties. This paper aims to establish the relationship between grain size reduction and wear and corrosion of AZ91 alloy. The wear performances of both coarse-grained and fine-grain alloy were conducted using L9 orthogonal array of experiments in order to study the effects of control parameters on wear performance. In the study, it has also been identified that through ECAP, the corrosion barrier and wear characteristics of the alloy were enhanced due to fine-grain-structure and the spheroidal precipitation of the second β-phase particles. Further, the influence of these changes on the performance of the AZ91 Mg alloy was assessed using SEM.
