scholarly journals Influence of Cold Rolled Deformation Degree and Heating Rates on Crystallite Dimension and Recrystallization Fraction of Aluminum Plates

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1428
Author(s):  
Yunlei Wang ◽  
Liping Ren ◽  
Jingren Dong ◽  
Chuanchuan Cao
Keyword(s):  
Pure Aluminum ◽  
Heating Rates ◽  
Initial State ◽  
Electron Backscattered Diffraction ◽  
Deformation Degree ◽  
High Deformation ◽  
Grain Boundary Characteristics ◽  
Crystallite Dimension ◽  
Cold Rolled ◽  
Aluminum Plates

In order to study the microstructure evolution rule of pure aluminum plates during different cold-rolled (CR) deformation degrees and annealing processes, samples with aCR deformation of 50~85%, heating rates of 60~100 °C/min and annealing at the target temperature of 350~500 °C were investigated. The microstructure, crystallite dimension and grain boundary characteristics were characterized by the methods of polarizing microscope (PM) and electron backscattered diffraction (EBSD). The results showed that the crystallite dimension of the initial state was 102 μm and ends up completely broken with an increase in the CR deformation degree. When the CR deformation increases to 85%, the deformed micro-bands were very small, with a band spacing of 5~10 μm. At this time, the grain distortion is more serious, there are more high-density grain defects, such as dislocations, and there is a high deformation of the storage energy, which is the energy preparation for the subsequent finished products to withstand the annealing process. The recrystallization fraction was higher with an increase in annealing temperature. After completed recrystallization, the grains showed an equiaxed shape. Orientation imaging and misorientation angle analysis showed that the red-oriented grains of the (001) plane, which had preferred nucleation, recrystallization and rapid grain growth. Final grains of the completed recrystallization are relatively coarse. Under the same deformation, the average crystallite dimension of the recrystallized grains decreases with an increase in annealing heating rate.

Local Microstructure Control of Pure Aluminum Utilizing Fiber-Laser Aided Spot Heating System

2007 ◽  
Vol 558-559 ◽  
pp. 329-332 ◽  
Author(s):  
Toshiya Shibayanagi ◽  
Masahiro Tsukamoto ◽  
Nobuyuki Abe ◽  
Takamasa Matsumoto ◽  
Y. Soga
Keyword(s):  
Fiber Laser ◽  
Pure Aluminum ◽  
Heating System ◽  
Present System ◽  
Minimum Diameter ◽  
The Matrix ◽  
Cold Rolled ◽  
Aluminum Plates ◽  
Laser Heated ◽  
Similar Crystallographic Orientation

Spot heating system utilizing a fiber-laser has been developed in order to control recrystallization, grain growth process and texture development. The newly developed system enables the laser beam to be focused onto the surface of specimen with a minimum diameter of around 10 m. The maximum power of laser in the present system is 100W. Specimens of cold rolled pure aluminum plates of 1mm thick are used for local recrystallization treatment by the spot heating. After laser-spot heating, preferentially recrystallized grains appeared in the irradiated and heat affected region with a diameter depending on the laser power density. The present system enables spot heating on any critical points of the specimen surface. Some laser-heated specimen show locally recrystallized regions occupied by almost single grain having similar crystallographic orientation as that of cold rolled matrix. But the orientation of recrystallized grain is not always the same as that of the matrix. Selective spot heating on grains having peculiar orientation would bring about a possibility of texture control that has not been achieved by means of conventional materials processing.

Microhardness and yield stress of cold rolled pure aluminum up to very high deformation

1983 ◽  
Vol 17 (2) ◽  
pp. 221-226 ◽  
Author(s):  
M. Zehetbauer ◽  
W. Pfeiler ◽  
J. Schrank
Keyword(s):  
Yield Stress ◽  
Pure Aluminum ◽  
High Deformation ◽  
Cold Rolled ◽  
Very High

An EBSD Study on Orientation Effects during Recrystallization of Coarse-Grained Niobium

2004 ◽  
Vol 467-470 ◽  
pp. 519-524 ◽  
Author(s):  
Hugo Ricardo Zschommler Sandim ◽  
Dierk Raabe
Keyword(s):  
Longitudinal Section ◽  
Primary Recrystallization ◽  
Coarse Grained ◽  
Subgrain Structure ◽  
Electron Backscattered Diffraction ◽  
Subgrain Growth ◽  
Metallographic Inspection ◽  
Cold Rolled ◽  
Cold Worked ◽  
Viable Mechanism

The recrystallization behavior of coarse-grained niobium depends on the nature of its deformation microstructure. In this regard, a longitudinal section of a high-purity coarse-grained niobium ingot was cold rolled to a thickness reduction of 96% followed by annealing in vacuum at 800°C for 1 h. Metallographic inspection in cold-rolled and annealed specimens was carried out in a field emission gun scanning electron microscope (FEG-SEM). Microtexture was determined by electron-backscattered diffraction (EBSD) coupled to the FEG-SEM. The use this technique has evidenced details of the boundary character and subgrain structure found in partially recrystallized regions. The early stages of primary recrystallization are associated to the presence of high-angle lamellar boundaries found in the cold-worked state. Abnormal subgrain growth has been evidenced as a viable mechanism for nucleation of recrystallization.

Correlation among Microstructure, Texture, and Properties along the Thickness Direction in As-Hot-Rolled and As-Solution-Quenched Al7055 Thick Plates

2021 ◽  
Vol 1026 ◽  
pp. 65-73
Author(s):  
Kai Zhu ◽  
Hong Wei Yan
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Tensile Tests ◽  
Rolled Plate ◽  
Uniaxial Tensile ◽  
Thickness Direction ◽  
Electron Backscattered Diffraction ◽  
Thick Plates ◽  
Aluminum Plates ◽  
Hot Rolled

Both microstructure inhomogeneity and mechanical property diversity along the thickness direction in rolled thick aluminum plates have been considered to have a remarkable impact on the performance and properties of the products made from the plates. In this study, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) characterizations of microstructure and texture types along the thickness directions of Al7055 thick plate specimens prepared using two conditions, hot-rolling and solution-quenching, were performed. To examine the mechanical properties, uniaxial tensile tests were also carried out on specimens machined from both types of thick plates, using a layered strategy along the thickness direction. The results indicate that both the microstructure and mechanical properties are inhomogeneous under the two conditions. Furthermore, it is evident that there is a hereditary relationship between the mechanical properties of the two plates—areas with higher yield strength in the as-hot-rolled plate correspond to areas with the higher yield strength in the as-solution-quenched plate

Micro-Embossing Process in Ultrafine-Grained Pure Aluminum Processed by Equal-Channel Angular Pressing with Elevated Temperature

2019 ◽  
Vol 821 ◽  
pp. 244-249
Author(s):  
Qian Su ◽  
Jie Xu ◽  
Lei Shi ◽  
De Bin Shan ◽  
Bin Guo
Keyword(s):  
Equal Channel Angular Pressing ◽  
Deformation Temperature ◽  
Pure Aluminum ◽  
Confocal Scanning Laser Microscopy ◽  
Electron Backscattered Diffraction ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Scanning Laser Microscopy ◽  
Confocal Scanning ◽  
Confocal Scanning Laser

Micro-embossing tests were performed on ultrafine-grained pure Al processed by equal-channel angular pressing (ECAP) with 100 μm width of female die at different deformation temperature ranging from 298 K to 523 K under a force of 5 kN. The filling height, surface topography and microstructure of the cross section were measured by confocal scanning laser microscopy (CSLM), scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD), respectively. The effects of deformation temperature on formability of ultrafine-grained (UFG) pure Al during micro-embossing were analyzed. The results show that increase in deformation temperature can improve the formability of UFG pure Al on micro-embossing. Micro hot embossing of UFG pure aluminum is characterized by the rib sidewall, surface quality, and fully transferred patterns, which shows ultrafine-grained pure Al has potential application in micro-forming.

Progress of Recrystallisation in Cold Rolled Austenitic Stainless Steel during Cyclic Thermal Process

2011 ◽  
Vol 702-703 ◽  
pp. 627-630
Author(s):  
B. Ravi Kumar
Keyword(s):  
Retained Austenite ◽  
Thermal Process ◽  
Annealing Treatment ◽  
Ultrafine Grain ◽  
Electron Backscattered Diffraction ◽  
Aisi 304L ◽  
Grain Formation ◽  
Strain Induced Martensite ◽  
Cold Rolled ◽  
Evolution Of Microstructure

The present study aims to understand the evolution of microstructure leading to nano/ultrafine grain formation during cyclic thermal process. A commercial grade of AISI 304L austenitic SS was cold rolled which resulted in a creation of a dual microstructure having strain induced martensite (43%) and heavily deformed retained austenite. The dual phase microstructure was subjected to cyclic thermal annealing process at 825 °C. The events occurring in; a) retained austenite and b) reverted austenite formed by phase reversion of strain induced martensite, during annealing treatment, were studied by the Electron backscattered diffraction (EBSD). The study revealed recrystallisation process of the two austenite grains, which resulted into ultrafine grain formation during cyclic thermal process.

Effects of Driving Force and Boundary Migration Velocity on Formation of Recrystallization Texture in Cold Rolled Pure Aluminum Sheets

2013 ◽  
Vol 753 ◽  
pp. 257-262 ◽  
Author(s):  
Wei Min Mao ◽  
Ping Yang
Keyword(s):  
Grain Growth ◽  
Driving Force ◽  
Recrystallization Texture ◽  
Pure Aluminum ◽  
Solute Drag ◽  
Texture Formation ◽  
Oriented Growth ◽  
Aluminum Sheets ◽  
Zener Drag ◽  
Cold Rolled

The effects of net driving force for migration of high angle grain boundaries were emphasized beside many other factors which could influence the process of texture formation during recrystallization annealing of 95% cold rolled pure aluminum sheets. The net driving force consists basically of stored energy. However, it could be reduced by recovery, boundary drag, solute drag and Zener drag in different extents, in which only boundary drag is mis-orientation dependent. It was indicated that both oriented nucleation and oriented growth have obvious influence on recrystallization texture, and how far they influence the texture depends also on the level of net driving force when the grain growth starts during annealing. Oriented growth, which is induced by the differences in boundary drag of differently oriented grains, and the corresponding texture formation, could be observed easily when the recrystallization proceeds under relative higher solute drag and Zener drag in commercial purity aluminum. The oriented nucleation process prevails during recrystallization of sufficiently recovered high purity aluminum with very low solute drag and Zener drag, after which strong cube texture forms. In this case the oriented growth indicates limited effect. Both the oriented growth and oriented nucleation will fail if high purity deformation matrix without clear solute drag and Zener drag has not experienced an obvious recovery before recrystallization grain growth, since extremely high net driving force leads to very small critical nucleus size and multiplicity of growing grains, which results in randomization of recrystallization texture.

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.

Analysis of the Recrystallization of Cold-Rolled Copper after Isothermal Annealing Using Electron Backscattered Diffraction Patterns

2010 ◽  
Vol 297-301 ◽  
pp. 359-364 ◽  
Author(s):  
M. Matsushita ◽  
H. Ohfuji
Keyword(s):  
Pattern Analysis ◽  
Isothermal Annealing ◽  
Fiber Texture ◽  
Recrystallization Process ◽  
Random Orientation ◽  
Electron Backscattered Diffraction ◽  
Round Shape ◽  
Resolution Electron ◽  
Cold Rolled ◽  
Diffraction Patterns

Recrystallization processing of cold-rolled copper after isothermal annealing was investigated using high-resolution electron backscattered diffraction pattern analysis. The fiber texture is obtained by cold rolling with the rolled direction oriented along {111}, and the transverse and nominal directions have a random orientation. An isothermal recrystallization process at 150°C was investigated. Initially, rotations of the orientations occur from {111} to {100} and then small misfit angle boundaries decreased. Accompanying this change, the fiber-shaped grains change to a round shape grain and their sizes decrease. Considering these tendencies, we determined that rotation at subgrain boundaries is activated by isothermal annealing and subboundaries grow the boundary misfit angle >15 º. With further annealing, those grains surrounded by grain boundaries greater than 15º expanded. The rolling, transverse, and nominal orientations rotate {100}. Subsequently, a twin boundary appeared, and the fraction of twin boundaries increased.

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