Formability of ultrafine-grained interstitial-free steel fabricated by accumulative roll-bonding and subsequent annealing

2011 ◽  
Vol 65 (3) ◽  
pp. 175-178 ◽  
Author(s):  
Rika Yoda ◽  
Kosuke Shibata ◽  
Takatoshi Morimitsu ◽  
Daisuke Terada ◽  
Nobuhiro Tsuji
Keyword(s):  
Accumulative Roll Bonding ◽  
Subsequent Annealing ◽  
Interstitial Free ◽  
Roll Bonding ◽  
Ultrafine Grained ◽  
Interstitial Free Steel

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.

Lamellar Subdivision during Accumulative Roll Bonding of a Titanium Interstitial Free Steel

2005 ◽  
Vol 495-497 ◽  
pp. 351-356 ◽  
Author(s):  
Ana Carmen C. Reis ◽  
Leo Kestens ◽  
Yvan Houbaert
Keyword(s):  
Shear Strain ◽  
Accumulative Roll Bonding ◽  
Rolling Direction ◽  
Orientation Imaging Microscopy ◽  
Lamellar Microstructure ◽  
Composite Sample ◽  
Interstitial Free ◽  
High Angle ◽  
Roll Bonding ◽  
Interstitial Free Steel

Titanium alloyed interstitial free steel was processed by means of accumulative roll bonding (ARB) in order to obtain an ultrafine grained structure. Ten consecutive rolling passes were applied at 480°C with a nominal reduction of 50% per pass and an intermediate annealing treatment of 5 min. at 500°C. A total true strain was obtained of evM = 8.0 which corresponds to an accumulated reduction of 99.9%. Orientation imaging microscopy was used to evaluate textures and microstructures. A pronounced lamellar structure was observed until the 5th pass with an incidence of high angle grain boundaries predominantly parallel to the rolling direction. After the 6th pass (evM = 4.8) an increased fragmentation perpendicular to the rolling direction starts to develop in spite of the lamellar microstructure with an average spacing of approximately 1 µm. From the 7th pass onwards (evM ≥ 5.6) a random high angle grain boundary distribution develops which results in a more equi-axed ultrafine microstructure after the 9th pass (evM = 7.2) with an average grain width of 200 nm. As the rolling is carried out without lubrication, the surface areas display a slightly more fragmented structure than the midlayer sections and typical shear texture components are present in these surface zones (<110>//ND and <211>//ND fibre). Although the sheets are stacked upon each other after each subsequent pass, the shear strain microstructural and textural features are rapidly decomposed in the midlayer in each subsequent rolling pass which is clearly revealed by the cross sectional orientation scan on the composite sample. Hence it cannot be concluded that the surface shear strain significantly contributes to the grain fragmentation in the bulk volume of the composite sample.

Susceptibility to Hydrogen Embrittlement of IF Steel with Ultrafine-Grained Structure Produced by Accumulative Roll-Bonding Process

2010 ◽  
Vol 654-656 ◽  
pp. 1235-1238 ◽  
Author(s):  
Takumi Haruna ◽  
Yuichi Nakagawa ◽  
Daisuke Terada ◽  
Naoki Takata ◽  
Nobuhiro Tsuji
Keyword(s):  
Hydrogen Embrittlement ◽  
Accumulative Roll Bonding ◽  
Fracture Strain ◽  
Cathodic Current Density ◽  
Interstitial Free ◽  
If Steel ◽  
Cathodic Current ◽  
Roll Bonding ◽  
Charging Time ◽  
Ultrafine Grained

We have investigated the susceptibility to hydrogen embrittlement of interstitial-free (IF) steel with ultrafine-grained microstructure produced by accumulative roll-bonding (ARB) process. The ARB process was conducted to as-received IF steel at 773 K, and repeated to five cycles. The as-received and the ARBed IF steels were cut into tensile specimens, and then hydrogen was electrochemically charged to the specimens in a sulfuric acid solution of pH 2.5 at a cathodic current density of 50 A m-2 for several charging times. Immediately after the hydrogen-charging process, tensile test was conducted at ambient temperature and an initial strain rate of 3.3 x 10-4 s-1. Besides, state and amount of hydrogen absorbed in the specimen were determined with a thermal desorption gas spectroscopy (TDS) at a heating rate of 5.6 x 10-2 K s-1. As a result, almost no hydrogen was absorbed in the as-received IF steel charged for a long time of ca. 300 ks, and a fracture strain of the steel was independent of the charging time. On the other hand, amount of hydrogen in the 5-cycle ARBed steel increased with an increase in the charging time, and the fracture strain decreased with an increase in the charging time, indicating that the ARBed steel exhibited susceptibility to hydrogen embrittlement.

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.

An Assessment of Bulk and Local Stored Energy Measurements in Ultrafine Grained Interstitial Free Steel

2010 ◽  
Vol 89-91 ◽  
pp. 244-249 ◽  
Author(s):  
Sujoy S. Hazra ◽  
Azdiar A. Gazder ◽  
Elena V. Pereloma
Keyword(s):  
Profile Analysis ◽  
Energy Estimates ◽  
Internal Stresses ◽  
Line Profile Analysis ◽  
Interstitial Free ◽  
Stored Energy ◽  
Scanning Calorimetry ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Interstitial Free Steel

The evolution of stored energy and associated thermal behaviour was investigated for an ultrafine grained Ti-IF steel severely deformed by Equal Channel Angular Pressing (ECAP) followed by cold rolling at ambient and liquid nitrogen temperatures. Bulk stored energy measurements by Differential Scanning Calorimetry (DSC) returned 350-600 whereas local stored energy estimates from microhardness, Electron Back-Scattering Diffraction (EBSD) and X-ray line profile analysis resulted in 5-140 . Higher bulk stored energy values correspond to the enthalpy release from all sources of strain in the material volume as well as Ti precipitation during annealing while the lower local stored energy range alludes only to dislocation content or internal stresses. An apparent activation energy of 500-550 suggests sluggish recrystallisation due to excess of Ti in solid solution.

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