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Online since: June 2014
Authors: Hua Cui, Tao Tao Sun, Lin Zhong Zhuang, Long Gang Hou, Ming Xing Guo, Wang Tu Huo, Ji Shan Zhang
Microstructure evolution and information (e.g., grain size, grain shape, misorientation angle distribution, grain size distribution) was characterized and analyzed by optical microscopy (OM), H800 TEM and EBSD equipment.
After annealing 3 s at 673 K, the deformed microstructures just start to recrystallize (Fig. 3), some fine grains could be seen around the boundary of deformation bands and the number of recrystallized grains increased with annealing time.
After 10 s, deformed AA7075 Al alloy is fully recrystallized with fine-elongated grains, and the grain size and shape are unchanged with extending times, as shown in Fig. 3.
The recrystallized AA7075 Al alloy exhibits a fairly steady fine-grained structures with ~10 μm mean grain size with different recrystallizing and solutionizing processes.
The Erichsen test results of present AA 7075 Al alloy with different grain sizes (6-25 μm) acquired by different recrystallizing schedule show the good formability is acquired with ~10 μm mean grain size, which gives an Erichsen value of 7.34 mm, and neither larger nor finer grain was in favor of formability.
After annealing 3 s at 673 K, the deformed microstructures just start to recrystallize (Fig. 3), some fine grains could be seen around the boundary of deformation bands and the number of recrystallized grains increased with annealing time.
After 10 s, deformed AA7075 Al alloy is fully recrystallized with fine-elongated grains, and the grain size and shape are unchanged with extending times, as shown in Fig. 3.
The recrystallized AA7075 Al alloy exhibits a fairly steady fine-grained structures with ~10 μm mean grain size with different recrystallizing and solutionizing processes.
The Erichsen test results of present AA 7075 Al alloy with different grain sizes (6-25 μm) acquired by different recrystallizing schedule show the good formability is acquired with ~10 μm mean grain size, which gives an Erichsen value of 7.34 mm, and neither larger nor finer grain was in favor of formability.
Online since: November 2005
Authors: John J. Jonas, Simon P. Ringer, Ilana B. Timokhina, S. Bulcock, Elena V. Pereloma
The alloyed steels
displayed an increase in the number of grains containing shear bands and strengthening of the {111}
component after warm rolling compared to an unmodified low carbon steel [7].
Discussion The recrystallisation process and the final recrystallisation texture depend on the stored energy and the number and configuration of dislocations present in the deformed material.
The stored energy level is sensitive to the number of interstitial atoms present in the plane.
The higher values of stored energy in the LC steel are related to the higher amount of carbon in solid solution and, in turn, to the lower number of grains containing shear bands.
As reported by Barnett [13], a small number of deformed grains containing shear bands promoted the formation of a weak {111} recrystallisation component in this steel since the γ fibre forms preferentially at shear band boundaries.
Discussion The recrystallisation process and the final recrystallisation texture depend on the stored energy and the number and configuration of dislocations present in the deformed material.
The stored energy level is sensitive to the number of interstitial atoms present in the plane.
The higher values of stored energy in the LC steel are related to the higher amount of carbon in solid solution and, in turn, to the lower number of grains containing shear bands.
As reported by Barnett [13], a small number of deformed grains containing shear bands promoted the formation of a weak {111} recrystallisation component in this steel since the γ fibre forms preferentially at shear band boundaries.
Online since: June 2014
Authors: Heng Zhang, Zhao Tang Xu, Kun He
The germination characteristics such as germination rate, germinating, germination index, vigor index, and content changes of protein and nucleic acid in wheat grain were determined by germination bed method.
The contents of protein and nucleic acid in the grains affect on the seed germination and growth [2].
Germination rate/% = (Germination number / total of grain number for test) ×100% Germinating /% = (Germination number within 3days/ total of grain number for test) ×100% Germination index = Gt/Dv, Gt for germination number in t days, Dt for days Vigor index = G1S, G1 for germination index, S for sum the length of bud plus root Results and Discussions Effect of extract concentration of disused battery on wheat germination Wheat grain was placed in germination bed including the extract of disused battery for 216h, observing swell level of wheat germ every day, recording the change of germination per 100 wheat grains, the results are shown in Fig. 1, x axis is the extract concentration of disused battery, y axis is the germination rate, and z axis is the wheat grain culture time.
The wheat grains were soaked in 0%, 15%, 30%, 50% and 70% of extract concentration respectively.
The synthesis metabolism of nucleic acid is dominant with the increase of cell number during seed germination, the content of nucleic acid in cell enhance quickly.
The contents of protein and nucleic acid in the grains affect on the seed germination and growth [2].
Germination rate/% = (Germination number / total of grain number for test) ×100% Germinating /% = (Germination number within 3days/ total of grain number for test) ×100% Germination index = Gt/Dv, Gt for germination number in t days, Dt for days Vigor index = G1S, G1 for germination index, S for sum the length of bud plus root Results and Discussions Effect of extract concentration of disused battery on wheat germination Wheat grain was placed in germination bed including the extract of disused battery for 216h, observing swell level of wheat germ every day, recording the change of germination per 100 wheat grains, the results are shown in Fig. 1, x axis is the extract concentration of disused battery, y axis is the germination rate, and z axis is the wheat grain culture time.
The wheat grains were soaked in 0%, 15%, 30%, 50% and 70% of extract concentration respectively.
The synthesis metabolism of nucleic acid is dominant with the increase of cell number during seed germination, the content of nucleic acid in cell enhance quickly.
Online since: January 2020
Authors: A.G. Barbosa de Lima, C.M. Rufino Franco, Vera Solange de Oliveira Farias, E. Andriola Machado
Truncation error analysis.For the accuracy of the solution, a minimum number of base functions is necessary.
This analysis proved that the drying rate increases with increasing number of pauses.
b) Application to drying of rice grains with husk.
In addition, the drying rate increases with increasing number of pauses.A diffusion model was proposed to describe continuous and intermittent drying of rice grains with husk.
[2] M.J.Milman,Equipments for pre-processing of grain.
This analysis proved that the drying rate increases with increasing number of pauses.
b) Application to drying of rice grains with husk.
In addition, the drying rate increases with increasing number of pauses.A diffusion model was proposed to describe continuous and intermittent drying of rice grains with husk.
[2] M.J.Milman,Equipments for pre-processing of grain.
Online since: February 2018
Authors: Xin Bing Yun, Ying Zhao, Tian Tian, Cong Wang, Hong Zhan
With the increase of deformation degree, the number of shear bands increased.
A few small grains about 20 μm were found in the grains about 50μm.
A large number of slip bands were found in the grains.
The small grains have been found in the grain boundaries.
A large number of recrystallized grains exists in the upper area and edge of large grains in middle area.
A few small grains about 20 μm were found in the grains about 50μm.
A large number of slip bands were found in the grains.
The small grains have been found in the grain boundaries.
A large number of recrystallized grains exists in the upper area and edge of large grains in middle area.
Online since: July 2020
Authors: Hao Zhu, Shao Kang Dong, Ze Ming Ma, Jun Wang
Currently, a large number of efforts have been done to investigate the FSW of aluminum alloys.
The HAZ remains the same grain structure as the BM and the grain has a certain extent of coarsening with respect to the BM as is shown in Fig. 1(e) &Fig. 1(b).
The TMAZ experienced plastic deformation with a certain extent of strain hardening effect and the number of MgZn2 increases while the number of AlCuMg decreases.
In the HAZ, the number of the MgZn2 increases and the number of the AlCuMg decrease further, respectively.
When the rotational speed is 800r/min, the number of MgZn2 decreases while the number of AlCuMg increases, as is shown in Fig. 7 (b).
The HAZ remains the same grain structure as the BM and the grain has a certain extent of coarsening with respect to the BM as is shown in Fig. 1(e) &Fig. 1(b).
The TMAZ experienced plastic deformation with a certain extent of strain hardening effect and the number of MgZn2 increases while the number of AlCuMg decreases.
In the HAZ, the number of the MgZn2 increases and the number of the AlCuMg decrease further, respectively.
When the rotational speed is 800r/min, the number of MgZn2 decreases while the number of AlCuMg increases, as is shown in Fig. 7 (b).
Online since: April 2021
Authors: M.V. Mukhina, G.V. Pachurin, A.N. Kuzmin
During thermal cycling of titanium with an initial superheated structure, thermal stresses after a certain number of cycles can lead to intragranular plastic deformation, and subsequent recrystallization annealing lead to grain refinement [17, 18].
The number of TCT cycles varied from 1 to 50.
Grain refinement occurs after the first cycle of the TCT (dnom. = 700 microns).
With an increase in the number of cycles, a grain decrease corresponds to an increase in the fatigue limit, which reaches a maximum value (σ-1 = 220-230 MPa) after 10-15 cycles of TCT (dnom. = 245-219 microns).
In our case, the fatigue limit reaches this level with a decrease in the grain size by ~ 3.3 times, which is possibly determined not only by the grain size itself, but also by the method of its production and, in particular, the formation of subgrains with grain-boundary angle in several degrees at the optimal number of TCT cycles, which serve as an additional obstacle to the spread of plastic deformation [24].
The number of TCT cycles varied from 1 to 50.
Grain refinement occurs after the first cycle of the TCT (dnom. = 700 microns).
With an increase in the number of cycles, a grain decrease corresponds to an increase in the fatigue limit, which reaches a maximum value (σ-1 = 220-230 MPa) after 10-15 cycles of TCT (dnom. = 245-219 microns).
In our case, the fatigue limit reaches this level with a decrease in the grain size by ~ 3.3 times, which is possibly determined not only by the grain size itself, but also by the method of its production and, in particular, the formation of subgrains with grain-boundary angle in several degrees at the optimal number of TCT cycles, which serve as an additional obstacle to the spread of plastic deformation [24].
Online since: November 2009
Authors: Sergey V. Dobatkin, Yuri Estrin, T.D. Rostova, Valerij V. Zakharov, O.G. Ukolova, A. Tchirkova
Mechanical characteristics of the initially cast Al-Mg-Zr and Al-Mg-Zr-Sc alloys as a
function of the number of ECAP passes.
As seen from the graphs, the strength of the alloys increases with the number of ECAP passes.
The best result in terms of ductility was achieved with the Al-Mg-Zr-Sc alloy by applying 6 passes of ECAP. 100 150 200 250 300 350 0 2 4 6 8 Number of passes YS, MPa 270 290 310 330 350 370 390 410 430 450 0 2 4 6 8 Number of passes UTS, MPa 20 25 30 35 40 45 0 2 4 6 8 Number of passes RA,% 10 12 14 16 18 20 0 2 4 6 8 Number of passes EL,% Al-Mg-Mn-Zr Al-Mg-Mn-Zr-Sc Fig. 11.
This is considered to be the mechanism responsible for the finer grain structure (with the average grain size of 850 nm) in the Al-Mg-Zr-Sc alloy.
Valiev, in: Recrystallization and Grain Growth, edited by G.
As seen from the graphs, the strength of the alloys increases with the number of ECAP passes.
The best result in terms of ductility was achieved with the Al-Mg-Zr-Sc alloy by applying 6 passes of ECAP. 100 150 200 250 300 350 0 2 4 6 8 Number of passes YS, MPa 270 290 310 330 350 370 390 410 430 450 0 2 4 6 8 Number of passes UTS, MPa 20 25 30 35 40 45 0 2 4 6 8 Number of passes RA,% 10 12 14 16 18 20 0 2 4 6 8 Number of passes EL,% Al-Mg-Mn-Zr Al-Mg-Mn-Zr-Sc Fig. 11.
This is considered to be the mechanism responsible for the finer grain structure (with the average grain size of 850 nm) in the Al-Mg-Zr-Sc alloy.
Valiev, in: Recrystallization and Grain Growth, edited by G.
Online since: March 2013
Authors: Patrick Baud, Teng Fong Wong, Yun Tao Ji, Li Qiang Liu
With this segmentation, we obtained statistics on macropores on intact and deformed Indiana limestone which shows that inelastic compaction was followed by a significant reduction in the number of macropores.
A number of isolated blobs (in red) can be identified in the macroporosity zone.
There is an overall decrease by a factor ~2 in the number of macropores with respect to the undeformed rock (Fig. 5).
The partitioning between solid grains, macroporosity and the intermediate zone dominated by microporosity are shown.
With this segmentation, we obtained statistics on macropores on intact and deformed Indiana limestone which shows that inelastic compaction was followed by a significant reduction in the number of macropores.
A number of isolated blobs (in red) can be identified in the macroporosity zone.
There is an overall decrease by a factor ~2 in the number of macropores with respect to the undeformed rock (Fig. 5).
The partitioning between solid grains, macroporosity and the intermediate zone dominated by microporosity are shown.
With this segmentation, we obtained statistics on macropores on intact and deformed Indiana limestone which shows that inelastic compaction was followed by a significant reduction in the number of macropores.
Online since: December 2011
Authors: M. Thirumurugan, R. Madhavan, S. Kumaran, T. Srinivasa Rao, Satyam Suwas
However, their applicability is hindered due to the poor workability owing to the hexagonal close-packed (HCP) crystal structure and consequent limitations on the number of available slip systems [1].
Microstructure of the ZM21 alloy reveals single phase with an average grain size ~ 400µm and AZ91 alloy shows α-Mg and continuous b (Mg17Al12) precipitates along the grain boundary.
The recrystallized grain size is in the range 20-30µm.
However, the presence of β-phase in AZ91 may facilitate grain refinement by inducing large strain adjacent to the grain boundary and inhibit the growth of recrystallized grains.
At high temperatures, as in the present case, bulging of existing grain boundaries controlled by dislocation climb results in the formation of new DRX grains.
Microstructure of the ZM21 alloy reveals single phase with an average grain size ~ 400µm and AZ91 alloy shows α-Mg and continuous b (Mg17Al12) precipitates along the grain boundary.
The recrystallized grain size is in the range 20-30µm.
However, the presence of β-phase in AZ91 may facilitate grain refinement by inducing large strain adjacent to the grain boundary and inhibit the growth of recrystallized grains.
At high temperatures, as in the present case, bulging of existing grain boundaries controlled by dislocation climb results in the formation of new DRX grains.