Relationship between Strength and Grain Size of Friction Stir Processed and Annealed High Purity Aluminum

2014 ◽  
Vol 922 ◽  
pp. 372-375
Author(s):  
Sho Kobayashi ◽  
Tomo Kawakatsu ◽  
Yorinobu Takigawa ◽  
Tokuteru Uesugi ◽  
Kenji Higashi
Keyword(s):  
Grain Size ◽  
Chemical Composition ◽  
Yield Stress ◽  
Coarse Grain ◽  
Petch Relation ◽  
Friction Stir ◽  
Grain Sizes ◽  
Fine Grain ◽  
High Purity Aluminum ◽  
The Relationship

A relationship between yield stress and grain size was examined in FSP-ed and annealed 5N-Al (99.9996% purity) in order to reveal the relationship on materials with equal chemical composition, because the large positive deviations of yield stress from the Hall–Petch relation obtained by plots with coarse grain size were reported in the fine grain sizes with SPD processed and we focused on amount of impurities during SPD processing about this phenomenon. The purity of FSP-ed samples on this study were 99.9988% Al (Fe +8at.ppm). Annealing this sample at various temperatures, the relationship between yield stress and grain sizes was obtained on materials with equal chemical composition. However, the yield stress of sample as FSP-ed is higher than that following Hall-Petch relation obtained by subsequently annealed samples plots. As a result, the positive deviation is occurred by factors other than the impurities.

Effect of Solute Elements on Grain Refinement during Friction Stir Processing in High-Purity Aluminum

2016 ◽  
Vol 838-839 ◽  
pp. 116-121 ◽  
Author(s):  
Tokuteru Uesugi ◽  
Hideaki Iwami ◽  
Yorinobu Takigawa ◽  
Kenji Higashi
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Friction Stir Processing ◽  
High Purity ◽  
Critical Role ◽  
Hollomon Parameter ◽  
Friction Stir ◽  
Grain Sizes ◽  
Purity Level ◽  
High Purity Aluminum

Friction stir processing (FSP) is one of the severe plastic deformation (SPD) processes. It has been reported that SPD-processed Al with various purities attained a minimum grain size when Zener-Hollomon parameter is larger than 1016 s-1. The minimum grain size is different by purity level and alloying elements. We investigated the influence of Fe solute atoms on grain refinement of high-purity Al on the condition that Zener-Hollomon parameter was larger than 1016 s-1. FSP was conducted on Al-0.01%Fe, which was fabricated by using 5N Al (99.999% purity). FSP-ed Al-0.01%Fe exhibits the minimum grain size of 1.4 μm, although high-purity aluminums with more than 99.998% exhibits much larger minimum grain sizes of 30-40 μm. Only 101 at.ppm Fe played a critical role in the grain refinement of pure aluminums.

The Method of Eliminating Banded Structure and the Effects of Banded Structure on the Transverse Properties in 20G Steel

2013 ◽  
Vol 347-350 ◽  
pp. 1171-1175 ◽  
Author(s):  
Bin Wang ◽  
Hong Mei Hu ◽  
Cui Zhou
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Stress Concentration ◽  
Base Metal ◽  
Metallic Inclusion ◽  
Banded Structure ◽  
Grain Sizes ◽  
Fine Grain ◽  
Treatment Processes ◽  
Metallic Inclusions

The transverse properties were inferior to the longitudinal properties for the existence of banded structure in 20G steel. In order to eliminate the banded structure and improve the transverse performance of 20G steel, different heat treatment processes were adopted. The results showed that conventional normalizing could reduce the banded structure and refine the grain sizes. When 20G was heated with 10°C/min heating rated and then held at 920°C for 2h, the banded structure in the steel was almost eliminated and the microstructure was homogeneous with fine grain size, the strength increased by 14%. The non-metallic inclusion and carbide in the microstructure leaded to stress concentration and separation with the base metal. To some extent, heat treatment can improve the distribution and form of non-metallic inclusions.

scholarly journals Effect of Grain Size on Carburization Characteristics of the High-Entropy Equiatomic CoCrFeMnNi Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7199
Author(s):  
Hyunbin Nam ◽  
Jeongwon Kim ◽  
Namkyu Kim ◽  
Sangwoo Song ◽  
Youngsang Na ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Grain Sizes ◽  
Fine Grain ◽  
Cast Specimen ◽  
Vacuum Carburization ◽  
Cold Rolled ◽  
Face Centered

In this study, the carburization characteristics of cast and cold-rolled CoCrFeMnNi high-entropy alloys (HEAs) with various grain sizes were investigated. All specimens were prepared by vacuum carburization at 940 °C for 8 h. The carburized/diffused layer was mainly composed of face-centered cubic structures and Cr7C3 carbide precipitates. The carburized/diffused layer of the cold-rolled specimen with a fine grain size (~1 μm) was thicker (~400 μm) than that of the carburized cast specimen (~200 μm) with a coarse grain size (~1.1 mm). In all specimens, the carbides were formed primarily through grain boundaries, and their distribution varied with the grain sizes of the specimens. However, the carbide precipitates of the cast specimen were formed primarily at the grain boundaries and were unequally distributed in the specific grains. Owing to the non-uniform formation of carbides in the carburized cast specimen, the areas in the diffused layer exhibited various carbide densities and hardness distributions. Therefore, to improve the carburization efficiency of equiatomic CoCrFeMnNi HEAs, it is necessary to refine the grain sizes.

Features for friction stir welding of butt joints of casting VAL8 alloy with wrought 1565chN2 and AMg6M alloys

2021 ◽  
pp. 441-449
Author(s):  
V.A. Berezina ◽  
V.V. Ovchinnikov ◽  
E.V. Luk'yanenko
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Chemical Composition ◽  
Arc Welding ◽  
Butt Joints ◽  
Friction Stir ◽  
Discrete Nature ◽  
Casting Aluminum ◽  
Tool Rotation

The results of technological features for friction stir welding of butt joints of sheet blanks with thickness of 3 mm made of casting aluminum V AL8 alloy with wrought magnalium group 1565chN2 and AMg6M alloys are presented. It is established that the time resistance of the joints depends on the location of the welded alloys relative to the direction of tool rotation during friction stir welding. The ultimate strength of welded joints of VAL8 alloy with 1565chN2 and AMg6 alloys in automatic argon-arc welding is 0.82...0.84 of the ultimate tensile strength of VAL8 alloy. The grain size in the stir zone practically does not depend on the initial grain size in the alloys to be joined. The destruction of the joints made of VAL8 + 1565chH2 alloys under cyclic loading has multi-focal character and is initiated from irregularities on the surface of the weld. The discrete nature of the change in the chemical composition of the weld metal along the axis of the weld is revealed. The weld is formed by alternating strips of connected alloys with width of 30...90 microns.

Research and Development of U68CuCr Rail Steel

2012 ◽  
Vol 482-484 ◽  
pp. 989-995
Author(s):  
Yu Ji ◽  
Zhong Min Yang ◽  
Min Zhu ◽  
Wan Ling Zhang
Keyword(s):  
Grain Size ◽  
Chemical Composition ◽  
Research And Development ◽  
Production Process ◽  
Rail Steel ◽  
High Strength ◽  
Immersion Test ◽  
Corrosion Resistant ◽  
Fine Grain ◽  
Hot Rolled

According to characteristics of the marine environment corrosion, 980MPa steel were developed. After design rational chemical composition and production process, the full section hot-rolled corrosion-resistant sorbite rail steel were successfully developed. this kind of steel has fine grain size, high strength and perfect toughness. Dry-wet immersion test showed that lift of this rail is 70% longer than U75V.

Microstructure Prediction by Finite Element Analysis during Hot Rolling of Magnesium Alloy Sheets

2015 ◽  
Vol 661 ◽  
pp. 105-112
Author(s):  
Yeong Maw Hwang ◽  
Tso Lun Yeh
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Optimal Conditions ◽  
Compression Tests ◽  
Element Analysis ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Microstructure Prediction ◽  
Alloy Microstructure ◽  
The Relationship

Material’s plastic deformation by hot forming processes can be used to make the materials generate dynamic recrystallization (DRX) and fine grains and accordingly products with more excellent mechanical properties, such as higher strength and larger elongation can be obtained. In this study, compression tests and water quenching are conducted to obtain the flow stress of the materials and the grain size after DRX. Through the regression analysis, prediction equations for the magnesium alloy microstructure were established. Simulations with different rolling parameters are conducted to find out the relationship between the DRX fractions or grain sizes of the rolled products and the rolling parameters. The simulation results show that rolling temperature of 400°C and thickness reduction of 50% are the optimal conditions. An average grain size of 0.204μm-0.206μm in the microstructure is obtained and the strength and formability of ZK60 magnesium alloys can be improved.

Thermal and mechanical characterization of polymer composites filled with dispersed zeolite and oil shale

2010 ◽  
Vol 45 (11) ◽  
pp. 1209-1216 ◽  
Author(s):  
A.M. Zihlif ◽  
Ziad Elimat ◽  
G. Ragosta
Keyword(s):  
Thermal Conductivity ◽  
Grain Size ◽  
Yield Stress ◽  
Oil Shale ◽  
Activation Volume ◽  
Filler Concentration ◽  
Grain Sizes ◽  
Eyring Theory ◽  
Zeolite Composite

The thermal, viscoelastic, mechanical behavior of polymers filled with dispersed zeolite and oil shale is studied as a function of temperature, grain size, and filler concentration. It was found that the thermal conductivity of epoxy—zeolite composite increases with different zeolite grain sizes and takes a higher value in case of the 63 μm grain size composite. The observed enhancement in the thermal conductivity of zeolite composites correlates well with that of the electrical conductivity. The thermodynamic results exhibit a slight increase in the glass transition temperature of the polystyrene/oil shale composites, and shift in the observed relaxation peaks with increasing the oil shale content. The plastic deformation of PS/oil shale composites shows that the elastic modulus increases and the compressive yield stress decreases with oil shale content. The Eyring theory of yielding could predict the dependence of the yield stress on the applied strain rate. The predicted activation volume and activation energy showed dependence on the oil shale grains sizes and content.

Effects of Various Cooling Techniques on Grain Refinement of Aluminum 7075-T651 During Friction Stir Processing

2016 ◽  
Author(s):  
Vivek V. Patel ◽  
Vishvesh J. Badheka ◽  
Samarth R. Zala ◽  
Sagar R. Patel ◽  
Utsav D. Patel ◽  
...  
Keyword(s):  
Grain Size ◽  
Friction Stir Processing ◽  
Weight Ratio ◽  
Optical Microscope ◽  
Process Temperature ◽  
Friction Stir ◽  
Fine Grain ◽  
State Process ◽  
Structural Applications ◽  
Aluminum 7075

Aluminum 7075 alloy (AA 7075) is one of the prime materials used in the aviation and automotive industry because of its high strength to weight ratio, good amount of fatigue strength and high machinability. Friction stir processing (FSP) is one of the emerging solid state process that refines the microstructure and hence improved mechanical properties are obtained. The process temperature during FSP affects the resulting microstructure so the attempt for reducing the process temperature can result into reduction in the grain size. The fine grain size microstructure delivers high percentage of elongation which reduces the number of joints and welds in the critical structural applications. So, by implementing coolants such as water and carbon dioxide (CO2) during this process had hindered the grain growth and very fine grained microstructure was obtained. The fine grain microstructure offers higher elongation and hardness as deformation starts from the grain boundaries. In this experimental investigation we intended to keep the temperature generation during the process as low as possible by keeping the process parameters of 765 rpm, 31.5 mm/min fees rate and 20 tilt of the tool (optimized for tapered threaded cylindrical pin tool) constant. All the samples were examined by metallographic characterization using optical microscope. The grain size measurements for all three FSP samples were carried out. Water and CO2 cooled FSP samples reported much more fine grain as compared to naturally cooled sample because of the less heat input during the process.

Study on the Effect on Sintering Mineralization of Iron Ore

2013 ◽  
Vol 652-654 ◽  
pp. 2538-2542 ◽  
Author(s):  
Xiao Hui Fan ◽  
Ying Li ◽  
Xu Ling Chen
Keyword(s):  
Grain Size ◽  
Regression Analysis ◽  
Chemical Composition ◽  
Iron Ore ◽  
Raw Material ◽  
Sintering Process ◽  
Main Effect ◽  
Relationship Model ◽  
Ore Mineralization ◽  
The Relationship

The main effect on iron ore mineralization performance in the sintering process is the grain size of raw material and chemical composition. The results show that -0.5mm particles can mineralize, but +0.5mm particles remain a nucleus in sinter. This paper analyses the effect of the chemical composition on mineralization characteristics of liquid production. The relationship model is established by using regression analysis between the chemical composition and liquid formation characteristics. The mian factors of mineralization in the chemical composition: SiO2, CaO, MgO and Al2O3.

Effect of Temperature and Grain Size on the Corrosion Behavior of 316L Stainless Steel in Seawater

2011 ◽  
Vol 299-300 ◽  
pp. 175-178 ◽  
Author(s):  
Sen Sen Xin ◽  
Jian Xu ◽  
Feng Jun Lang ◽  
Mou Cheng Li
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Corrosion Behavior ◽  
316L Stainless Steel ◽  
Seawater Temperature ◽  
Effect Of Temperature ◽  
Coarse Grain ◽  
Pitting Potential ◽  
Fine Grain ◽  
Different Grain Size

The corrosion behavior of 316L stainless steel was investigated in seawater at different temperature by using cyclic anodic polarization. The results indicated that two 316L specimens with different grain size showed similar pitting potential at 25°C. The increase of seawater temperature led to the linear decrease of pitting potential and repassivation potential. Because the pitting resistance of fine grain steel reduced larger than that of coarse grain steel with increasing temperature, the latter had a higher pitting potential about 60 mV at 85°C. Compared with the coarse grain steel, the fine grain steel showed a longer induction time for pitting at 65°C.

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