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Among the isometric crystals, some stripe-like annealing twins are found, but with the increasing C content, the number of annealing twins decreased.
The strain stripes as well as deformation twins become less denser as the C content increases, and the percentage of grains in which deformation twinning did not become higher.
C penetrate into the octahedral interstice of the austenitic grains after they undergo solution treatment and hot-rolling successively.
It is predicted that deformation induced twinning results in a large number of twin boundaries (TBs).
TBs acts as a role that is similar to grain refinement, which shorten the effective distance of the dislocation motion.

The chemical stabilization of g phase is enhanced by the small grain size decreasing martensite start temperature [12].
There are lath regions and more blocky grains in the microstructure of the 3Mn steel whereas the 5Mn steel is characterized by the presence of laths with a various thickness.
However, some blocky grains of the 3Mn steel (Fig. 2a) are transformed into martensite at 450°C whereas interlath austenite is more stable.
The thermomechanically rolled samples show a similar grain refinement as axisymetrical samples despite lower number of passes and total strain applied.
The strong grain refinement makes it impossible to identify structural constituents using optical microscopy (Fig. 3a and b).

Plots of log10(fer) against log10f for the SBTR at a number of fixed temperatures.
According to (1), the great decrease of A(T) indicates that the conductivity drops greatly because a large number of carriers are becoming more and more frozen with decreasing T.
The inset in Fig.4 (a) gives the high f section of the Nyquist plot and two arcs are obviously shown, which should be ascribed to the grain and grain boundary responses, respectively [2].
Meanwhile, only a small section of grain boundary arcs shows a steep incline due to the high grain boundary R at low f.
By the best fitting, Ucond~0.12eV is obtained, i.e. the activation energy for charge migration inside grains (grains response).

For this purpose, a number of samples made from GTD-111 superalloy have been coated by powder cementation method and have been subjected to rapture test and have been compared to uncoated samples.
The average grain size of the first γ´ sedimentary phase is about 0.85 µm and the average grain size of the secondary γ´ sedimentary phase is about 0.1 µm.
Fig.1(b) and 1(c) show the carbide phases of type MC and M23C6 which are scattered inside the grains and in grain boundary as embossed particles.
Fig.1- SEM image from microstructure of GTD-111 superalloy: (a): the images of the first and secondary γ´ sedimentary phases, (b): the MC carbide particles distributed in alloy matrix, (c): the image of the grain boundary and observation of M23C6 boundary grain carbide, (d): eutectic γ´- γ.

The process gives typically inclusions that are lower in number and slightly larger than those obtained by the MA process.
Image analysis was used to determine the size and volume number density of small inclusions from TEM bright-field images.
These samples were ∅ 4mm drawn wires and grain size was therefore smaller that that of the tube walls.
A fine-grained recrystallised structure is maintained for long times at high temperatures without significant grain growth.
Creep properties substantially improved over existing RSP FeCrAl alloys makes the new alloy interesting for a number of high temperature application areas.

Grain refinement (GR) is widely acknowledged as a technique for producing UFG aluminum alloys.
The grain sizes decreased to 0.2 µm, which improved the strength of the material.
The grain size, grain boundaries orientations were investigated by EBSD and the optical microscope OLYMPUS BX51M.
When Compared to Fig. 7a, the dimples in Fig. 7b, are larger, deeper, and more likely to merge, and there are a smaller number of Sc dispersoids on the fracture surface.
The fracture morphology shows a large number of recrystallized grains and coalescence of dimples.

A number of new Mg-Al alloys series with additions of various alloying elements have been developedto date in order to gain better high temperature mechanical properties, especially high temperature creep property, which is a major requirement for use of magnesium in automotive powertrain components.
Furthermore, the continuous network of interphases can inhibit the grain boundary sliding and impede the movement of dislocation.
The distribution of grain boundary phases does not have obvious changes after annealing at 400oC for 200h.
Annealing at 400oC results in obviously decrease of creep property due to the morphological change of the grain boundary intermetallics.
It is proposed that the continuous network distribution of compounds along grain boundaries plays a major role in restrictingthe creep deformation of Mg-Al alloy at elevated temperatures, and the grain boundary sliding becomes an important creep mechanism for the alloy studied.

Thus, it can be inferred that with the Ce and Ca additions to the RS/PM Mg-6Zn alloy, the number of Mg-Zn binary phases decreased remarkably.
%Ce, the grains of the RS/PM Mg-6Zn-5Ce alloy was refined remarkably, with the size of 500nm-1μm, and the number of fine dispersed particles with the size of approximately 90nm-260nm increased substantially, especially around the grain boundaries.
%Ca (Fig. 3(c)), the grains of the alloy were further refined, with the size of 200- 650nm.
A large number of precipitates with relatively larger size and a few fine precipitates were distributed at the grain boundary and in the grain interior, respectively.
Moreover, it was reported that the grain size of an alloy after DRX varied as a function of the Zener-Hollomon parameter (Z), and the relationship between the values of Z and the grain size varied with the compositions of the alloys [26].

Fig. 9(a) shows there are no sharp grains protruding and most diamond abrasive particles are leveled or embedded in bond.
Fig. 9(c) shows the wheel surface topography after dressing (90V, 3.3A, 60kHz, 75%), where some diamond abrasives protrude on the surface of the wheel and the iron bond among diamond grains are also removed.
Fig. 9(d) shows wheel surface topography after dressing (120V, 6.6A, 40kHz, 75%), Fig. 8 Diagram of factor effect on profile accuracy 40 60 12 10 8 Frequency f/kHz 3.3 6.6 10 11 10 9 Current I/A Profile accuracy/ µm 60 90 120 11 10 9 Voltage U/V 25 50 75 15 10 5 Duty cycle D/% Fig.7 Photograph of surface profile measurement result of the dressed wheel (a) without dressing (b) Run number 1 (c) Run number 4 (d) Run number 8 Fig.9 Wheel surface topography (SEM).
(3) The wheel profile accuracy can reach upward 0.8µm after dressing, the protrusion heights of diamond grain were uniformity and the protrusion effect was better than without dressing.
Acknowledgements The author gratefully acknowledge the National Natural Science Fund of China for their Support of this work: The contact number is 50875066.

The results showed that fractal dimension for limestone powder specific surface area has a good linear relationship with median grain diameter and RR-B value.
Zheng Zhongshan, Yu Ke and other researchers found that the size distribution of a large number of powder materials have fractal structure [4], met in the Formula (1)
And there is a maximum value between the fractal dimension Table 5.The grain size characteristic value and specific surface areaof six kinds of limestone powder Table 6.
To the L1-L3 and L5-L7, the degree of association continued to decrease and the impact on the intensity of continued to reduce with the grain size increased.
Due to C3S’s hydration of cement, a large number of Ca2+ was produced.