Martensitic Transformation from Ultrafine Grained Austenite Fabricated by ARB in Fe-24Ni-0.3C

2010 ◽  
Vol 667-669 ◽  
pp. 361-366 ◽  
Author(s):  
Hamidreza Jafarian ◽  
Ehsan Borhani ◽  
Akinobu Shibata ◽  
Daisuke Terada ◽  
Nobuhiro Tsuji
Keyword(s):  
Martensitic Transformation ◽  
Accumulative Roll Bonding ◽  
Martensite Transformation ◽  
Early Stage ◽  
Crystallographic Analysis ◽  
High Angle ◽  
Metastable Austenite ◽  
Roll Bonding ◽  
Nucleation Sites ◽  
Ultrafine Grained

In this paper, martensitic transformation from ultrafine grained (UFG) austenite fabricated by accumulative roll bonding (ARB) process in a metastable austenite alloy was studied. Microstructural observations and crystallographic analysis were carried out by FE-SEM/EBSD. The results showed that elongated UFG austenite having 200-300 nm in thickness surrounded by high angle boundaries was obtained after 6 cycles of the ARB process. The martensite transformed from the UFG austenite showed characteristic morphology and texture. The martensite transformation starting (Ms) temperature increased after 1 cycle ARB, which is related to increasing amount of nucleation sites, such as low angle boundaries, introduced during early stage of ARB process. In contrast, by increasing the ARB cycles, Ms temperature decreased. Decreasing the Ms temperature could be correlated to strengthening of austenite by the ARB process.

Mechanical Properties and Aging Behavior of Ultrafine Grained Al-Ag Alloy Fabricated by Accumulative Roll-Bonding

2014 ◽  
Vol 794-796 ◽  
pp. 851-856
Author(s):  
Tadashiege Nagae ◽  
Nobuhiro Tsuji ◽  
Daisuke Terada
Keyword(s):  
Mechanical Properties ◽  
Grain Refinement ◽  
Accumulative Roll Bonding ◽  
Precipitation Hardening ◽  
Tensile Elongation ◽  
Solution Treatment ◽  
High Strength ◽  
Subsequent Aging ◽  
Roll Bonding ◽  
Ultrafine Grained

Accumulative roll-bonding (ARB) process is one of the severe plastic deformation processes for fabricating ultrafine grained materials that exhibit high strength. In aluminum alloys, aging heat treatment has been an important process for hardening materials. In order to achieve good mechanical properties through the combination of grain refinement hardening and precipitation hardening, an Al-4.2wt%Ag binary alloy was used in the present study. After a solution treatment at 550°C for 1.5hr, the alloy was severely deformed by the ARB process at room temperature (RT) up to 6 cycles (equivalent strain of 4.8). The specimens ARB-processed by various cycles (various strains) were subsequently aged at 100, 150, 200, 250°C, and RT. The hardness of the solution treated (ST) specimen increased by aging. On the other hand, hardness of the ARB processed specimen decreased after aging at high temperatures such as 250°C. This was probably due to coarsening of precipitates or/and matrix grains. The specimen aged at lower temperature showed higher hardness. The maximum harnesses achieved by aging for the ST specimen, the specimens ARB processed by 2 cycles, 4 cycles and 6 cycles were 55HV, 71HV, 69HV and 65HV, respectively. By tensile tests it was shown that the strength increased by the ARB process though the elongation decreased significantly. However, it was found that the tensile elongation of the ARB processed specimens was improved by aging without sacrificing the strength. The results suggest that the Al-Ag alloy having large elongation as well as high strength can be realized by the combination of the ARB process for grain refinement and the subsequent aging for precipitation hardening.

Ultra Grain Refinement of Low C Steels by Accumulative Roll Bonding

2006 ◽  
Vol 503-504 ◽  
pp. 311-316 ◽  
Author(s):  
I. Salvatori
Keyword(s):  
Accumulative Roll Bonding ◽  
Orientation Imaging Microscopy ◽  
Low Carbon Steel ◽  
Small Samples ◽  
Low Carbon ◽  
High Angle ◽  
Misorientation Distribution ◽  
Roll Bonding ◽  
Orientation Imaging ◽  
Annealing Conditions

Refinement of grain size is one of the biggest challenges to produce steels with improved combination of strength and toughness. Ultrafine structures are being produced world-wide on various materials, including low carbon steel, using different types of processes. However, the majority of these processes also exhibit severe limitations because they are generally restricted to small samples and are difficult to be implemented on an industrial scale. A promising technique for industrial implementation is the Accumulative Roll Bonding (ARB), a process able to supply large samples, even in the laboratory scale. In this paper, warm intense straining (ε = 4) by ARB was applied to a plain low-C steel in order to develop ultrafine grains, aiming at sizes around 1-2 μm, suitable to maintain an adequate combination of strength and ductility. The effect of annealing conditions on the evolution of the work-hardened microstructure and the bonding behaviour after each pass were investigated. Orientation Imaging Microscopy was used to investigate the microstructure and give a quantitative assessment of high angle and low angle boundaries. It is showed that the frequency of high angle grain boundaries increases with the strain but the misorientation distribution remained far from that typical of a recrystallised material.

scholarly journals An Experimental Study of Fracture Toughness for Nano/Ultrafine Grained Al5052/Cu Multilayered Composite Processed by Accumulative Roll Bonding

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
D. Rahmatabadi ◽  
B. Mohammadi ◽  
R. Hashemi ◽  
T. Shojaee
Keyword(s):  
Fracture Toughness ◽  
Stress Fracture ◽  
Plane Stress ◽  
Accumulative Roll Bonding ◽  
Uniaxial Tensile ◽  
Roll Bonding ◽  
Multilayered Composite ◽  
Maximum Value ◽  
Ultrafine Grained ◽  
Pure Cu

In this study, ultrafine grained Al5052/Cu multilayered composite has been produced by accumulative roll bonding (ARB) and fracture properties have been studied using plane stress fracture toughness. The fracture toughness has been investigated for the unprocessed specimens, primary sandwich and first, second, and third cycles of ARB process by ASTM E561 and compact tension (CT) specimens. Also, the microstructure and mechanical properties have been investigated using optical microscopy, scanning electron microscopy, uniaxial tensile tests, and microhardness measurements. The value of plane stress fracture toughness for the ultrafine grained Al5052/Cu composite increased by increasing the number of ARB cycles, continuously from the primary sandwich to end of the third cycle. The maximum value of 59.1 MPa m1/2 has been obtained that it is about 2.77 and 4.05 more than Al5052 and pure Cu (unprocessed specimens). This phenomenon indicated that ARB process and the addition of copper to aluminum alloy could increase the value of fracture toughness to more than three times. The results showed that by increasing the ARB cycles, the thickness of copper layers reduced and after the fifth cycle, the excellent uniformity of Cu layers achieved. By increasing the number of ARB cycles, the microhardness of both aluminum and copper layers have been significantly increased. The tensile strength of the sandwich has been enhanced continually, and the maximum value of 566.5 MPa has been achieved.

Review on Accumulative Roll Bonding (ARB) Techniques for Improving the Mechanical Properties of Multi-Layered Materials

2020 ◽  
Vol 979 ◽  
pp. 84-88
Author(s):  
A. Arun ◽  
Lakshmanan Poovazhgan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Accumulative Roll Bonding ◽  
Nanocrystalline Structure ◽  
Hardness Test ◽  
Roll Bonding ◽  
Transmission Electron ◽  
Ultrafine Grained ◽  
Materials Used ◽  
Number Of Passes

Accumulative Roll Bonding (ARB) is one among the techniques in Severe Plastic Deformation (SPD) which is used to produce ultrafine grains and nanocrystalline structure in the materials used. Tensile test, micro hardness test, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and bending tests are the various tests carried out to understand the grain refinement of ARB materials. ARB is carried out in homogenous and heterogeneous materials to bring out the useful applications of ultrafine grained materials. ARB process mainly carried out in room, warm and hot temperature. The variations in the structure of the material are obtained by changing the load applied on the roller and by increasing the number of passes. This review paper brings out how the mechanical properties of the materials are improved by ARB process

Plastic anisotropy of ultrafine grained aluminium alloys produced by accumulative roll bonding

2010 ◽  
Vol 527 (13-14) ◽  
pp. 3271-3278 ◽  
Author(s):  
B. Beausir ◽  
J. Scharnweber ◽  
J. Jaschinski ◽  
H.-G. Brokmeier ◽  
C.-G. Oertel ◽  
...  
Keyword(s):  
Accumulative Roll Bonding ◽  
Aluminium Alloys ◽  
Plastic Anisotropy ◽  
Roll Bonding ◽  
Ultrafine Grained

scholarly journals Microstructure and Mechanical Properties of Ultrafine-Grained Copper by Accumulative Roll Bonding and Subsequent Annealing

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5171
Author(s):  
Xueran Liu ◽  
Limin Zhuang ◽  
Yonghao Zhao
Keyword(s):  
Tensile Strength ◽  
Strain Hardening ◽  
Accumulative Roll Bonding ◽  
Shear Zones ◽  
Subsequent Annealing ◽  
Scale Production ◽  
Copper Sheet ◽  
Roll Bonding ◽  
Ultrafine Grained ◽  
Cumulative Strain

Recently, the accumulative roll bonding (ARB) technique has made significant progress in the production of various ultrafine-grained (UFG) metals and alloys. In this work, a UFG copper sheet was produced by ARB and subsequent annealing at 300 °C for 60 min to optimize strength and ductility. It was found that homogeneous lamellar UFG materials with a thickness of 200–300 nm were formed after six ARB passes. The microhardness and tensile strength of as-ARBed Cu increased, while the ductility and strain hardening decreased with the cumulative deformation strain. The as-ARBed specimens fractured in a macroscopically brittle and microscopically ductile way. After annealing, discontinuous recrystallization occurred in the neighboring interface with high strain energy, which was prior to that in the matrix. The recrystallization rate was enhanced by increasing the cumulative strain. UFG Cu ARBed for six passes after annealing manifested a completely recrystallized microstructure with grain sizes approximately ranging from 5 to 10 μm. Annealing treatment reduced the microhardness and tensile strength but improved the ductility and strain hardening of UFG Cu. As-annealed UFG-Cu fractured in a ductile mode with dominant dimples and shear zones. Our work advances the industrial-scale production of UFG Cu by exploring a simple and low-cost fabrication technique.

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