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Online since: February 2015
Authors: Jakub Antoš, Pavel Tesárek, Václav Nežerka
Strain gauges allow recording strains at a limited number of discrete points and do not provide sufficient amount of data, thus increasing the cost of the analysis.
Such approach has a number of disadvantages – the strain must be within a certain range, the deformation is averaged over the strain-gauge length, the measurement is limited to the strain-gauge location and the surface of the loaded element must be smooth enough to attach the gauge.
For that purpose a mortar composed of lime and Portland cement in ratio 7 : 3, and common river sand of grain size 0-2 mm in binder to aggregate mass ratio 1 : 3 was prepared.
Such approach has a number of disadvantages – the strain must be within a certain range, the deformation is averaged over the strain-gauge length, the measurement is limited to the strain-gauge location and the surface of the loaded element must be smooth enough to attach the gauge.
For that purpose a mortar composed of lime and Portland cement in ratio 7 : 3, and common river sand of grain size 0-2 mm in binder to aggregate mass ratio 1 : 3 was prepared.
Online since: July 2013
Authors: David M. Carrick, Simon Hogg, Geoffrey D. Wilcox
This has been achieved by effectively managing a number of factors, including the control of impurity elements, such as hydrogen and phosphorous that are present during the preparation of Li-containing alloys, as well as using grain refining elements such as Mn and Zr.
These help by assisting in pinning grain boundaries.
This was shown by the large number of pit sites surrounding the intermetallic particles.
Some of the pits on AA2024-T3 were a similar size to those on AA2099-T8E77 (~100 x 100 µm), however, most were smaller and the number of pits was also less, as illustrated in Fig. 1c.
Of the phases that are detrimental to corrosion, AA2024-T3 possesses the potential to include a number; Al2Cu and Al2Cu-Mg, whereas AA2099-T8E77 can also include; Al3Li and Al2CuLi.
These help by assisting in pinning grain boundaries.
This was shown by the large number of pit sites surrounding the intermetallic particles.
Some of the pits on AA2024-T3 were a similar size to those on AA2099-T8E77 (~100 x 100 µm), however, most were smaller and the number of pits was also less, as illustrated in Fig. 1c.
Of the phases that are detrimental to corrosion, AA2024-T3 possesses the potential to include a number; Al2Cu and Al2Cu-Mg, whereas AA2099-T8E77 can also include; Al3Li and Al2CuLi.
Online since: June 2014
Authors: Xiao Jing Zhang, Guo Fang Liu, Yong Qing Ma, Yu Fen Liang
Fig.1(b) for the microstructure of 1050℃ quenching of 6S1 steel the dislocation and twin martensites formed in grain each about 10μm, in which a little of very finely granular carbides distributed uniformly.
The highest tempering hardness and tempering temperature are relational to the carbide type and number of the corresponding precipitation strengthening.
Table 3 is the carbides composing and mole number of equilibrium carbides according to the calculation of experimental steels.
On the other hand, when adding appropriate ratio of W and Mo is of result in a large number of Mo into the M6C, the Mo content in M6C of 6S2 steel reached 38% and the relative ratio of M6C in the steel as well as increased, and then it is conducive to the precipitation focus at intermediate temperature, which can be see from difference values(D-value) of mole fraction at 540℃ and that at quenching temperature.
Edmonds, Effet of vanadium on the grain boundary carbide nucleeation of pearlite in high-carbon steels[J], Scripta Metallurgica et Materialia, 1994,30(10), p1251-1255 [8] Yang Zhang, Application of phase equilibrium thermodynamic method in alloy design for high carbon alloy steel with ultra fine Carbides[D], Dalian Maritime University, 2007,6(in Chinese) [9] Lee K B, Yang H R, Kwon H, Effects of alloying additions and austenitizing treatments on secondary hardening and fracture behavior for martensitic steels containing both Mo and W[J], Metallurgical and Materials Transactions A:2001,32(7):1659-1670
The highest tempering hardness and tempering temperature are relational to the carbide type and number of the corresponding precipitation strengthening.
Table 3 is the carbides composing and mole number of equilibrium carbides according to the calculation of experimental steels.
On the other hand, when adding appropriate ratio of W and Mo is of result in a large number of Mo into the M6C, the Mo content in M6C of 6S2 steel reached 38% and the relative ratio of M6C in the steel as well as increased, and then it is conducive to the precipitation focus at intermediate temperature, which can be see from difference values(D-value) of mole fraction at 540℃ and that at quenching temperature.
Edmonds, Effet of vanadium on the grain boundary carbide nucleeation of pearlite in high-carbon steels[J], Scripta Metallurgica et Materialia, 1994,30(10), p1251-1255 [8] Yang Zhang, Application of phase equilibrium thermodynamic method in alloy design for high carbon alloy steel with ultra fine Carbides[D], Dalian Maritime University, 2007,6(in Chinese) [9] Lee K B, Yang H R, Kwon H, Effects of alloying additions and austenitizing treatments on secondary hardening and fracture behavior for martensitic steels containing both Mo and W[J], Metallurgical and Materials Transactions A:2001,32(7):1659-1670
Online since: October 2014
Authors: Ewa Jonda, Krzysztof Lukaszkowicz
The number of cycles for each of the specimens has been established at 4000.
The dendrite grains at the boundary between the remelted and heat affected zones (RZ/HAZ) are fine, which is caused by the high temperature gradient.
With the use of the testing device, the coefficient of friction in the function of cycle number, has been evaluated (Fig. 3).
The sudden changes of the coefficient of friction that appear along some curves may result from the contact of the counter-specimen (Al2O3 ball) with the grains of adequate, undissolved in the laser treatment carbides.
The plot of the coefficient of friction depending on the number of cycles during the pin-on-disc test of X40CrMoV5-1 steel after alloying with TaC.
The dendrite grains at the boundary between the remelted and heat affected zones (RZ/HAZ) are fine, which is caused by the high temperature gradient.
With the use of the testing device, the coefficient of friction in the function of cycle number, has been evaluated (Fig. 3).
The sudden changes of the coefficient of friction that appear along some curves may result from the contact of the counter-specimen (Al2O3 ball) with the grains of adequate, undissolved in the laser treatment carbides.
The plot of the coefficient of friction depending on the number of cycles during the pin-on-disc test of X40CrMoV5-1 steel after alloying with TaC.
Online since: September 2013
Authors: Sheng Chuan Liu, Gui Ling Ding, Gang Chen
(2) Particle analysis
Test of fine-grained soil 0.075mm below is conducted using laser particle size analyzer and test results are shown in the figure below, which reflects that the microscopic structure of the cohesive soil is stable aggregates cemented by free oxides.
This is an important feature of high water content cohesive soil that is different from the general fine-grained soil. 2) According to the test statistics, the maximum intensity moisture content is generally less than the optimum moisture content from 0.2 to 0.3 in consistency, and the moisture content is more than from 6% to 10%.
Fig.7 Relationship between resilient modulus and freeze-thaw cycles (2) Relationship between resilient modulus and freeze-thaw cycle number Resilient modulus for the different compaction degree is shown in Figure 8.
Fig.8 Relationship between resilient modulus and the freeze-thaw cycle number It can be seen that the resilient modulus under each compaction degree decreases with the increase of freeze-thaw cycle number.
Table 3 Service life prediction of the highway under different subgrade strength ratio Strength ratio Load condition Maximum bending stress /MPa cleavage strength/MPa Fatigue effects number/ Million times Service life/year 1.5 standard load 0.18 0.6 2.64E+05 68.4 overload 0.20 0.6 5.82E+04 52.6 1 standard load 0.22 0.6 1.48E+04 38.5 overload 0.25 0.6 2.37E+03 20.5 0.75 standard load 0.25 0.6 2.24E+03 20.0 overload 0.29 0.6 3.55E+02 6.8 0.5 standard load 0.30 0.6 1.82E+02 4.0 overload 0.34 0.6 2.98E+01 0.8 Conclusions Through analysis of long-term performance of high water content soil subgrade, conclusions are made as follows: (1) High water content cohesive soil has such physical and mechanical properties as natural moisture content is generally between 20% and 45%, liquid limit is between 40% and 60%, clay content is generally over 40%, permeability coefficient is between 10-7~10-8cm/s, the CBR value is less than 5, the optimum moisture content is about 20 percent and maximum dry density
This is an important feature of high water content cohesive soil that is different from the general fine-grained soil. 2) According to the test statistics, the maximum intensity moisture content is generally less than the optimum moisture content from 0.2 to 0.3 in consistency, and the moisture content is more than from 6% to 10%.
Fig.7 Relationship between resilient modulus and freeze-thaw cycles (2) Relationship between resilient modulus and freeze-thaw cycle number Resilient modulus for the different compaction degree is shown in Figure 8.
Fig.8 Relationship between resilient modulus and the freeze-thaw cycle number It can be seen that the resilient modulus under each compaction degree decreases with the increase of freeze-thaw cycle number.
Table 3 Service life prediction of the highway under different subgrade strength ratio Strength ratio Load condition Maximum bending stress /MPa cleavage strength/MPa Fatigue effects number/ Million times Service life/year 1.5 standard load 0.18 0.6 2.64E+05 68.4 overload 0.20 0.6 5.82E+04 52.6 1 standard load 0.22 0.6 1.48E+04 38.5 overload 0.25 0.6 2.37E+03 20.5 0.75 standard load 0.25 0.6 2.24E+03 20.0 overload 0.29 0.6 3.55E+02 6.8 0.5 standard load 0.30 0.6 1.82E+02 4.0 overload 0.34 0.6 2.98E+01 0.8 Conclusions Through analysis of long-term performance of high water content soil subgrade, conclusions are made as follows: (1) High water content cohesive soil has such physical and mechanical properties as natural moisture content is generally between 20% and 45%, liquid limit is between 40% and 60%, clay content is generally over 40%, permeability coefficient is between 10-7~10-8cm/s, the CBR value is less than 5, the optimum moisture content is about 20 percent and maximum dry density
Online since: June 2021
Authors: Sergii Maksymov, Olena A. Prilipko, Аlla Radzievskaya, Julia Shepeliuk
As a result, in seams welded underwater, a large number of pores are observed, and the hydrogen content can be several times higher than the equilibrium one.
At the first stage, it was necessary to clarify the range of ACF parameters to reduce the number of experiments.
So, at a magnetic induction of 15 mT, the diameter of the overwhelming number of pores was in the range of 2 ... 10 μm, and only in some cases pores with a diameter of 13 ... 20 μm were encountered, Fig.2 c.
During metallographic studies, the structures of the weld metal and heat affected zone (HAZ) were studied in the following areas: overheating (large grain - I HAZ), crystalline modification (II HAZ), incomplete recrystallization (III HAZ), recrystallization (IV HAZ).
Near the fusion line (weld metal), as well as in I HAZ there is grain size refinement in 1.3…1.4 times.
At the first stage, it was necessary to clarify the range of ACF parameters to reduce the number of experiments.
So, at a magnetic induction of 15 mT, the diameter of the overwhelming number of pores was in the range of 2 ... 10 μm, and only in some cases pores with a diameter of 13 ... 20 μm were encountered, Fig.2 c.
During metallographic studies, the structures of the weld metal and heat affected zone (HAZ) were studied in the following areas: overheating (large grain - I HAZ), crystalline modification (II HAZ), incomplete recrystallization (III HAZ), recrystallization (IV HAZ).
Near the fusion line (weld metal), as well as in I HAZ there is grain size refinement in 1.3…1.4 times.
Online since: May 2017
Authors: Jacob Eapen, Ajay Annamareddy
It has been observed that irradiated UO2 undergoes swelling (attributed to the accumulation of gaseous and even nanoscale solid-like fission products) as well as polygonization – the division of each grain into 104 – 105 sub-grains, especially at the peripheral regions subjected to high burnup [23, 24].
Changes to the structure and porosity of the grains, along with the formation of defect clusters and dislocation loops have also been observed [25, 26].
As the knock energy increases, the cooperative displacements become more prominent as exemplified by the four peaks with the 10 keV knock, which is double the number observed for the 2 keV knock.
The histograms are normalized by the number of ions in their respective groups.
Uberuaga, Efficient annealing of radiation damage near grain boundaries via interstitial emission, Science 327 (2010) 1631-1634
Changes to the structure and porosity of the grains, along with the formation of defect clusters and dislocation loops have also been observed [25, 26].
As the knock energy increases, the cooperative displacements become more prominent as exemplified by the four peaks with the 10 keV knock, which is double the number observed for the 2 keV knock.
The histograms are normalized by the number of ions in their respective groups.
Uberuaga, Efficient annealing of radiation damage near grain boundaries via interstitial emission, Science 327 (2010) 1631-1634
Online since: April 2018
Authors: Yoichi Akagami, Hiroshi Tanaka, Yoshitugu Kawase
By reducing chipping and flank wear, one can reduce the tool costs related to cutting processes and reduce the number of times the insert has to be exchanged, leading to improved productivity.
By reducing chipping and tool wear, one can reduce tool costs related to cutting processes and reduce the number of times the insert is exchanged, thereby improving productivity.
Chou et al. showed that the wear resistance increases monotonically with decreasing cBN grain size [3].
Silicone fluid (KF-96; Shin-Etsu Silicone) was used as the polishing slurry in which 4-20 micrometer diamond or silicon carbide (SiC) grains were used as abrasives.
By reducing chipping and tool wear, one can reduce tool costs related to cutting processes and reduce the number of times the insert is exchanged, thereby improving productivity.
Chou et al. showed that the wear resistance increases monotonically with decreasing cBN grain size [3].
Silicone fluid (KF-96; Shin-Etsu Silicone) was used as the polishing slurry in which 4-20 micrometer diamond or silicon carbide (SiC) grains were used as abrasives.
Online since: December 2004
Authors: Henrik Larsson, Henrik Strandlund
Derivations of Eq. 1, or similar expressions, have been made by a number of
authors, see e.g.
a number of cells in order to evaluate the local composition and gradients.
The initial microstructure was a Voronoi construction consisting of 5 austenite grains, with the average grain radius set to 63 µm, and one small ferrite nucleus.
Fig. 4 shows the growth of the ferrite grain into the supersaturated austenite matrix.
During each time-step a large number of calls to Thermo-calc were made.
a number of cells in order to evaluate the local composition and gradients.
The initial microstructure was a Voronoi construction consisting of 5 austenite grains, with the average grain radius set to 63 µm, and one small ferrite nucleus.
Fig. 4 shows the growth of the ferrite grain into the supersaturated austenite matrix.
During each time-step a large number of calls to Thermo-calc were made.
Online since: February 2010
Authors: Sergey V. Dorozhkin
There have been a
number of major advances made in this field during the past 30 - 40 years.
Biomaterials and Bioceramics A number of definitions have been developed for the term "biomaterials".
A definite correlation between hardness and a grain size in sintered HA bioceramics was found: the hardness started to decrease at a certain critical grain size limit despite exhibiting high bulk density [104].
Furthermore, dense HA ceramics exhibit superplasticity at 1000 - 1100 °C with a deformation mechanism based on grain boundary sliding.
More to the point, bone-forming functions of cells can be dependent on grain morphology of the scaffolds.
Biomaterials and Bioceramics A number of definitions have been developed for the term "biomaterials".
A definite correlation between hardness and a grain size in sintered HA bioceramics was found: the hardness started to decrease at a certain critical grain size limit despite exhibiting high bulk density [104].
Furthermore, dense HA ceramics exhibit superplasticity at 1000 - 1100 °C with a deformation mechanism based on grain boundary sliding.
More to the point, bone-forming functions of cells can be dependent on grain morphology of the scaffolds.