Cold-Rolling and Subsequent Annealing of Ti-Rich Tial Polysynthetically Twinned (PST) Crystals

1990 ◽  
Vol 213 ◽  
Author(s):  
M.H. Oh ◽  
H. Inui ◽  
S.R. Nishitani ◽  
M. Yamaguchi
Keyword(s):  
Dislocation Density ◽  
Cold Rolling ◽  
Shear Deformation ◽  
Lamellar Structure ◽  
Room Temperature ◽  
Subsequent Annealing ◽  
Second Stage ◽  
Cold Rolled ◽  
Two Stages ◽  
Equiaxed Grains

ABSTRACTPolysynthetically twinned (PST) crystals of Ti-rich TiAl have been grown and specimens cut from these crystals have been rolled at room temperature and subsequently annealed at 900°C and 1000°C. When the shear deformation parallel to the lamellar boundaries occurs during rolling, PST crystals of Ti-rich TiAl can be rolled to about 50% reduction in thickness at room temperature.The recovery in microhardness occurs in two stages; the first stage associated with the decrease in dislocation density and the second stage connected with the annealing-out of deformation induced twins. The recrystallization mode depends on the amount of reduction. Up to 20% reduction, the lamellar structure is preserved even after the full recovery in hardness. When the amount of reduction exceeds 40%, a structure composed of equiaxed grains of TiAl is obtained after recrystallization. A mechanism of recrystallization of cold-rolled PST crystals, which may explain the dependence of recrystallization mode on the amount of reduction, is proposed.

Effect of Severe Cold-Rolling and Subsequent Annealing on Microstructure and Properties of in-Situ Composite Steel

2010 ◽  
Vol 667-669 ◽  
pp. 157-160
Author(s):  
Jun Zhao ◽  
Han Zhang ◽  
Yong Ming Yang ◽  
Jiu Chuan Chen ◽  
Quan Xing Wen ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Lath Martensite ◽  
Rolling Plane ◽  
Subsequent Annealing ◽  
Rolled Sample ◽  
In Situ Composite ◽  
Cold Rolling And Annealing ◽  
Cold Rolled ◽  
Equiaxed Grains

In this paper, the process of severe cold-rolling and annealing for Q235 steel with lath martensite has demonstrated a new promising technique for producing in-situ composite multi-nanolayer steel. Cold rolling and subsequent annealing have great impact on microstructure evolution as well as mechanical properties. In the as-rolled state, the strength (b 2112 MPa) is approximately four times increased than as-received material, which is attributed to work hardening and grain refining during cold rolling. As cold-rolled sample subjected to further annealing below 500 °C, deformed microstructure underwent further recovery and recrystallization and finally became refined equiaxed grains; ultrafine ferrite grains, nano-carbides precipitated uniformly were seen in the specimen annealed at 500 °C, and the phenomenon of fracture delamination was observed from the specimens, the delamination plane was parallel to the rolling plane, in-situ composite weak interfaces effect has great impact on the fracture surface. Annealing at and above 600 °C resulted in coarse ferrite grains with spheroidized coarse carbides, causing grain growth.

The Influence of Heat and Two Stages Precipitation in the Process of Natural Polymer Purification from the Byproduct of Bioethanol Process Base on Empty Palm Fruit Bunch

2015 ◽  
Vol 1123 ◽  
pp. 177-181
Author(s):  
Achmad Hanafi ◽  
Harry Budiman ◽  
Fauzan Aulia
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Room Temperature ◽  
Black Liquor ◽  
Ash Content ◽  
Natural Polymer ◽  
Palm Fruit ◽  
Second Stage ◽  
Direct Precipitation ◽  
Two Stages

The biopolymer material, lignin, was recovered from the black liquor by acidification of the black liquor using sulfuric acid. Several purification techniques were carried out to produce the high purity of lignin such as gradual precipitation of lignin from black liquor (first stage: precipitation at pH 7, second stage: precipitation at pH 2) and the diluting of crude lignin by sodium hydroxide then followed by re-precipitation at different temperature. Subsequently, the impurities of lignin product resulted from each purification techniques was determined as ash content that analyzed using temperature program furnace; and the content of lignin was investigated using spectrophotometer UV-Vis. The result showed that the content of lignin of material produced from gradual precipitation was approximately 77.6%. It was higher than the content of lignin about 3.4% of material produced from direct precipitation to pH 2. In addition, the elevating of temperature from 40 to 60°C was no considerably affect to the content of lignin in precipitate produced from re-precipitation of crude lignin solution in sodium hydroxide. Nonetheless, the content of lignin of precipitate improved 15% when the temperature of re-precipitation of crude lignin solution in sodium hydroxide was raised from room temperature to 40-60°C.

Cold-rolling of Ti-rich TiAl polysynthetically twinned crystals

1990 ◽  
Vol 5 (3) ◽  
pp. 484-487 ◽  
Author(s):  
S. R. Nishitani ◽  
M. H. Oh ◽  
A. Nakamura ◽  
T. Fujiwara ◽  
M. Yamaguchi
Keyword(s):  
Cold Rolling ◽  
Shear Deformation ◽  
Surface Texture ◽  
Room Temperature ◽  
Stoichiometric Composition ◽  
Rolling Direction ◽  
Rolling Plane ◽  
Total Reduction ◽  
Pole Figures

Polysynthetically twinned crystals of TiAl with a nearly stoichiometric composition have been grown and rolled at room temperature. The maximum total reduction in thickness which is attainable without fracture depends on lamellae orientation with respect to the rolling plane and rolling direction. When specimens are oriented such that shear deformation parallel to the lamellar planes is operative during rolling and its operation causes lengthening of specimens, such specimens can be rolled up to about 50% reduction in thickness. The (111) pole figures are determined for the surface of specimens rolled to several different amounts of reduction, and the formation of surface texture is briefly discussed.

Effect of Cold Rolling on the Damping of As Cast Cu-Al-Mn Shape Memory Alloys

2008 ◽  
Vol 137 ◽  
pp. 155-162 ◽  
Author(s):  
Agnieszka Mielczarek ◽  
Yvonne Wöckel ◽  
Werner Riehemann
Keyword(s):  
Dislocation Density ◽  
Cold Rolling ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Cold Work ◽  
Amplitude Dependence ◽  
Aluminium Content ◽  
Aging Effects ◽  
High Deformation ◽  
Cold Rolled

The ductility of Cu – Al – Mn shape memory alloys at room temperature depends on the aluminium content. High aluminium contents make Cu – Al – Mn very brittle and unsuitable for plastic shaping. Two Cu – Al – Mn shape memory alloys were investigated. The ductile alloy CuAl7.8Mn9.5 (all contents in wt. %) could be easily cold rolled by 86 %. The alloy CuAl12Mn4.3 could be cold rolled by only 12 - 14 %. The amplitude dependence of damping of austenitic specimens increased with increasing degree of cold work, whereas the damping of martensiticaustenitic specimens decreased. These observations can be explained by the creation of stress induced martensite and therefore by new moveable interfaces like phase- and twin boundaries, which contribute to damping. Plastic deformation increases the dislocation density, too. Both the increase of dislocation density and the increase of martensite content can lead to a decrease of damping mainly for high deformation degrees. Same shape memory alloys have shown negligible hardness increase during cold rolling, too. This behaviour, untypical for metals, can be explained by the generation of new martensite and by the fact that the hardness of martensite is smaller than the hardness of austenite. Some aging effects of the specimen after cold rolling, which lead to decrease of damping, were detected. This can be explained by pinning of moveable interfaces by point defects and/or retransformation of martensite into austenite.

Effect of Annealing Treatment on the Properties of Cold Rolled Copper Foil

2018 ◽  
Vol 921 ◽  
pp. 231-235
Author(s):  
Ke Bin Sun ◽  
Yan Feng Li ◽  
Ye Xin Jiang ◽  
Guo Jie Huang ◽  
Xue Shuai Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cold Rolling ◽  
Copper Foil ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Test Machine ◽  
Cold Rolled ◽  
Rolled Copper Foil ◽  
Fracture Morphologies

Copper foils with 91% cold rolled deformation annealed at temperature between 140°C and 170 °C.The microstructures were observed by EBSD. The mechanical properties were measured at room temperature by tensile test machine and the fracture morphologies observed by SEM. After annealed at 150 °C, recrystallization begins to occur, while the elongation increases evidently and tensile strength decreases sharply. When the temperature rises to 170 °C, recrystallization is complete and the grain starts to grow. When the foils are annealed at 140 °C, it exhibits a strong cold rolling textures characterized by Brass {011}<211> and Cu {112}<111>. After annealed at 170 °C, there are olny weak Brass {011}<211> texture.

scholarly journals Temporary Shelter Simulation Towards Effectiveness Value of OTTV and Thermal Comfort

2019 ◽  
Vol 36 (3) ◽  
Author(s):  
Dyah Puspa Ayu ◽  
Budi Prayitno ◽  
Agus Hariyadi
Keyword(s):  
Thermal Comfort ◽  
Natural Disasters ◽  
Room Temperature ◽  
Human Life ◽  
Air Humidity ◽  
Value Differences ◽  
Second Stage ◽  
Thermal Transfer ◽  
A Value ◽  
Two Stages

Indonesia is prone to a variety of natural disasters, one of which is earthquakes. Earthquakes are detrimental to human life, causing among other things a loss of shelter. As such, victims of earthquakes need basic assistance in the form of shelter, which the Indonesian government provides in the transition phase of emergency responses. Several innovations in the provision of temporary shelter have arisen in terms of packaging and fast unloading. This research aimed to examine the effective value of OTTV energy (overall thermal transfer value), differences in room temperature, and thermal comfort in existing temporary shelters. OTTV values and thermal comfort are adapted to Indonesia's humid tropical climate, which has a temperature ranging 24–30°C and air humidity of 75%. Temporary shelters were simulated with Rhinoceros and Grasshopper softwares. The simulation was carried out in two stages, with the first stage simulating the temporary shelter materials and the second stage simulating according to a predetermined standard. The results concluded that the effective value of OTTV with the use of Styrofoam-based shelter gives a value of 27.63 W/m2 with a decrease of up to 4.70 W/m2 and the temperature drops to 2–3°C.

Microstructure Characteristics and Mechanical Properties of in-Situ Composite Steel Processed by Severe Cold-Rolling and Subsequent Annealing

2010 ◽  
Vol 168-170 ◽  
pp. 889-894
Author(s):  
Jun Zhao ◽  
Zhi Wang ◽  
Han Zhang ◽  
Hong Yan Zhai ◽  
Quan Xing Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Lath Martensite ◽  
Rolling Direction ◽  
High Strength ◽  
Subsequent Annealing ◽  
Microstructure Characteristics ◽  
In Situ Composite ◽  
Cold Rolled

In this paper, Q235 steel was investigated in order to manufacturing ultra-high strength material. The process of severe cold-rolling and low temperature annealing of lath martensite effectively reduced the crystal size from about 300 nm to 20 nm, and introduced mass weak interfaces in steel, has been demonstrated a new promising technique for producing in-situ composite multi-nanolayer steel with ultra-high strength (b 2112 MPa). Cold rolling and subsequent annealing have great impact on microstructure evolution as well as material mechanical properties. In the as-rolled state, the strength is approximately four times increased than as-received material (hot-rolled state, b 515 MPa), which is attributed to work hardening and grain refining during cold rolling. As the cold-rolled sample subjected to further annealing below 500 , deformed microstructure underwent further recovery and recrystallization, finally became refined equiaxed grains, microstructure characteristics along rolling direction arrangement was decreased; In addition to ultrafine ferrite grains, nano-carbides precipitated uniformly in the specimen annealed at 500 , total elongation increased to 16%, the corresponding yield strength was 1208MPa, much higher than that of as-received samples. The phenomenon of fracture delamination was observed from the specimens, which were cold-rolled and annealed at 500 , and the delamination plane was parallel to the rolling plane. In-situ composite weak interfaces effect has great impact on the fracture surface.

Effect of Dislocation Distribution on the Yielding of Highly Dislocated Iron

2007 ◽  
Vol 539-543 ◽  
pp. 228-233 ◽  
Author(s):  
Setsuo Takaki ◽  
Y. Fujimura ◽  
Koichi Nakashima ◽  
Toshihiro Tsuchiyama
Keyword(s):  
Dislocation Density ◽  
Cold Rolling ◽  
Microstructural Change ◽  
Low Carbon ◽  
Proportional Limit ◽  
Proof Stress ◽  
Cold Rolled ◽  
Cold Worked ◽  
Carbon Martensite ◽  
Distributed Dislocations

Yield strength of highly dislocated metals is known to be directly proportional to the square root of dislocation density (ρ), so called Bailey-Hirsch relationship. In general, the microstructure of heavily cold worked iron is characterized by cellar tangled dislocations. On the other hand, the dislocation substructure of martensite is characterized by randomly distributed dislocations although it has almost same or higher dislocation density in comparison with heavily cold worked iron. In this paper, yielding behavior of ultra low carbon martensite (Fe-18%Ni alloy) was discussed in connection with microstructural change during cold working. Originally, the elastic proportional limit and 0.2% proof stress is low in as-quenched martensite in spite of its high dislocation density. Small amount of cold rolling results in the decrease of dislocation density from 6.8x1015/m-2 to 3.4x1015/m-2 but both the elastic proportional limit and 0.2% proof stress are markedly increased by contraries. 0.2% proof stress of cold-rolled martensite could be plotted on the extended line of the Bailey-Hirsch equation obtained in cold-rolled iron. It was also confirmed that small amount of cold rolling causes a clear microstructural change from randomly distributed dislocations to cellar tangled dislocations. Martensite contains two types of dislocations; statistically stored dislocation (SS-dislocation) and geometrically necessary dislocation (GN-dislocation). In the early deformation stage, SS-dislocations easily disappear through the dislocation interaction and movement to grain boundaries or surface. This process produces a plastic strain and lowers the elastic proportional limit and 0.2% proof stress in the ultra low carbon martensite.

scholarly journals Enhancement of First Hydrogenation of Ti1V0.9Cr1.1 BCC Alloy by Cold Rolling and Ball Milling

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3106
Author(s):  
Salma Sleiman ◽  
Anis Aliouat ◽  
Jacques Huot
Keyword(s):  
Cold Rolling ◽  
Ball Milling ◽  
Mechanical Treatment ◽  
Room Temperature ◽  
Milling Time ◽  
Storage Capacity ◽  
Cast Alloy ◽  
Body Centered Cubic ◽  
Hydrogen Capacity ◽  
Cold Rolled

In this study, we evaluated the effects of a mechanical treatment by cold rolling (CR) and ball milling (BM) on the first hydrogenation of Ti1V0.9Cr1.1 alloy. The as-cast alloy has a body-centered cubic (BCC) crystal structure, and the first hydrogenation at room temperature under 20 bars of hydrogen is practically impossible. However, the samples mechanically activated by CR or BM readily absorbed hydrogen. The sample cold-rolled for one pass exhibited faster kinetics than the sample ball-milled for five minutes, but both samples reached the same storage capacity of 3.6 wt % hydrogen. Increasing the amount of rolling or the milling time decreased the hydrogen capacity. CR is considered the best and most efficient method for the activation of Ti1V0.9Cr1.1 alloy.

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