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And it’s characterized by a 2-3 grain size number (Fig. 1) according to the scale of macrostructures of titanium alloys [13].
Part of the boundaries of β-grains is bordered by a thin grain-boundary α-rim.
A different orientation of the colonies of the primary α-phase plates inside the grain is observed.
Typical grain (a) and intragranular (b) structure of VT23 tube The study of the structure by transmission electron microscopy is shown that the plates in the α-colonies do not contain a large number of dislocations (Fig. 3 a), but some of them are twinned and the twins break the plate into a series of parallel-oriented fragments (Fig. 3 b).
This provided the formation of a coarse-grained polyhedral recrystallized β-structure with a low dislocation density.

Effect of Cr content of grain boundary precipitates on creep-rupture property of heat-resistant steel Super304H Fig. 5 shows the variation of Cr content ((CCr)GBs) with count number frequency (R) of particles precipitated along grain boundaries in two groups of austenitic steel Super304H tube samples (WJ and SM) which experienced creep rupture tests at 700℃ and in a series of externally applied stress levels, respectively.
It is seen that the Cr concentration of grain boundary precipitate particles corresponding to a certain level of the R determined by the EPMA-EDS + MPSM increased with decreasing stress level and increasing creep-rupture time for the bulk steel samples.
The parameter Ka is defined as , showing the increased level of Cr partitioning in the grain boundary precipitate particles for a ruptured sample investigated.
This phenomenon indicates that the lower the stress level applied, the longer the rupture time experienced, and accordingly the higher the concentration in Cr in the grain boundary precipitates acquired in the ruptured samples, which reveals the fact that the Cr content of the grain boundary precipitates reflects directly their phase stability of the tube samples.
Fig. 1 Comparison of observed g¢ volume fractions [1-17] with those predicted by the present MPSM for some Ni-base superalloys Fig. 3 Comparison of observed g¢ lattice parameters [5,6,8,16,19-21] with those predicted by the present established calculation method for some Ni-base superalloys Fig. 5 Cr content ((CCr)GBs) vs. count number frequency (R) of grain boundary precipitate particles in two groups of creep-ruptured samples (SM and WJ) tested at 700℃ for Super304H Fig. 2 Comparison of observed TCP phase volume fractions [5] with those predicted by the present MPSM for some Ni-base superalloys Fig. 4 Evolution of the SRO parameters of Re in MC simulation Fig. 6 The externally applied stress level and Cr concentration distribution parameter Ka of grain boundary precipitate particles vs. creep rupture time in two groups of creep-ruptured samples (SM and WJ) tested at 700℃ for Super304H Table 1 g¢ volume fraction of

The above results indicate that a higher spinning rate is always beneficial for enhancing the diffusion ability of hydrogen atoms in the alloys, for which the refined grain and the increased internal stress by melt spinning are mainly responsible due to diffusion coefficient be directly proportional to the internal strain [8].
Fig.5 shows the cycle number dependence of the discharge capacity of the alloys, at a charging-discharging current density of 20 mA/g.
The enhanced discharge capacity of the alloys is basically ascribed to the refinement of the grain and the formation of an amorphous phase due to the fact that the hydrides mainly exist in grain-boundary and amorphous phase regions [9].
The capacity retaining rates of the La0 and La2 alloys as a function of the cycle number are depicted in Fig.6.
The grain refinement produced by melt-spinning exerts a negligible effect on the anti-corrosion capability of the alloy, which is the major reason why Fig.6 Evolution of the capacity retaining rate of the alloys with cycle number: (a) La0 alloy, (b) La2 alloy the melt spinning nearly did not show a helpful impact on the cycle stability of the La0 alloy.

Such modification of copper-based alloys is promising in a number of ways.
As a result, fine-grained microstructure of casts is obtained.
Such fine-grained structure holds higher strength properties in comparison with conventional microstructure.
Secondly, incorporating additional particles of nanopowder – grain nuclei – will allow the temperature interval of alloy crystallization to reduce.
Doping melts with nanopowders is accompanied by a number of problems.

Grinding wheels and micro surfaces of theirs abrasive grains Table2 Dressing parameters of the grinding wheels Grinding wheel truing Grinding wheel dressing finishing tool 80#SiC roller Dressing tool 200# alumina blocks Linear speed of grinding wheels (m/s) 4.5 Width of strip （mm） 30 Linear speed of finishing roller (m/s) 0.4(fixed value) Linear speed of grinding wheels (m/s) 30 Speed of the worktable (mm/min) 200 Speed of the worktable (mm/min) 200 Single side feed range (μm) 2 feed range (mm) 0.1 Feed number 100 Feed number 200 Dressing overlap ratio 2 2.3 Experimental parameters The experiments use up-grinding.
HEDG experiment parameters Number Wheel veloeity vs（m/s） Worktable speed vw（m/min） Deepth ap（mm） 1 60, 100, 130, 160, 180 1.0 0.1 2 180 0.5, 1.0, 1.5 3.0, 5.0, 7.0, 10.0 1.0 3 180 1.0 (2.0) 1.0, 1.5, 2.0, 2.5, 3.0 4 180 0.1 3.0, 4.0, 5.0, 6.0 3.
The maximum thickness (hmax) of un-deformed chips is an important physical quantity in the moulds of abrasive grains and it also influence abrasion of grinding wheels and machining surface integrity are impacted [6][7].
On the condition that a certain amount of the material is removed, with the maximum un-deformed thickness decreasing, grinding grains and the material’s interference paths become longer.
Note: this project get foundation from the Science and Technology major projects MKW5230A/3*160 large precise CNC gantry rail grinder of "high-grade CNC machine tools and basic manufacturing equipment" (project number: 2011 zx04003-011).

The surface was polished with emery papers of grain number from #200 to #1500 and was finished up to a mirror plane by buffing with diamond powder of 1μm grain diameter.
The load cycle number N was recorded when the specimen fractured.
In addition, the refined grain ahead of the crack tip is beneficial for improving the strength of material[11].
Furthermore, the small grain size in austenite steel can increase the threshold value of crack propagation and reduce the crack growth rate[13].
Acknowledgements The authors appreciate the financial supports from Liaoning Science & Technique Project (20161064) , Fundamental Research Funds for the Central University (Grant number 3132016012 and 3132017014) and Key Laboratory of Ship-Machinery Maintenance and manufacture for Ministry of Transportation (Grant number KF-2016-05).

This step will allow maximizing the number density of precipitates available during tempering stage.
Size and number density of M23C6 carbides is very similar after both ausfoming deformation.
The number density of these carbides was calculated to be in the order of 1019 (m-3).
Regarding the number density, both conditions under study exhibited a number density in the order of 1022 (m-3).
Similar size and number density of MX nanoprecipitates and M23C6 precipitates was obtained for both ausformed tempered martensites.

Phase identification showed single phase of MgTiO3(PDF number #790831).
In all cases grain growth were detected during sintering.
Average grain sizes were 2.3µm for MZTA, 3.4 µm for MZTB, and 1.8µm for MZTC.
It showed the role of B2O3 and Bi2O3 liquid phases were to reduce sintering temperature, however they cause grain growth.
Reece, Effect of Porosity and Grain Size on the Microwave Dielectric Properties of Sintered Alumina, J.

The abstract of the paper began as: “The grain structure of a casting is commonly described in terms of alloy composition, cooling rate, and nucleation.
It showed that metal flowing past columnar grains causes the grains to grow in the “upstream’’ direction, and explained the result in terms of the then quite new work of Bruce Chalmers and his students on “supercooling” in dendritic growth.
We were delighted to see the columnar grains that grew in the first case pointed nicely upstream.
The casting at the bottom of the figure had its end plugged so filling occurred as in a usual casting; the result was a largely equiaxed grain structure.
Utech, Process for Making Solids and Products Thereof, Patent Number 3,464,812; issued September 2, 1969

A number of nickel-based superalloy with high stacking fault energy was undergone room and high temperature deformation.
Microstructures become more homogeneous and grain growth rate is increased.
The mean grain size after recrystallization, disregarding twinning, was about 41-45μm with increasing cobalt.
Shear bands and grain boundaries were identified as preferential nucleation sites at 1473K.
All of the samples undergo continuous recrystallization, grain size was gradually decreased with cobalt addition. 5.