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The number of carbon atoms adsorbed by edge dislocation increases with bulk concentration increasing and temperature decreasing.
Moreover, the interaction energy between dislocation and solute atoms changes with the number of carbon atoms already adsorbed by dislocation.
Fig. 1 Maximum carbon atom number adsorbed by edge dislocation in austenite.
In the lower bainite region nucleation occurs at existing austenite grain boundaries, but there is a tendency for it to occur more frequently within the grain [12].
This indicates that defects within the grains, i.e. dislocations, might be favorable sites for nucleation of bainite plates.

Grain size influences mechanical properties and grain coarsening retards densification upon sintering, thus resulting in the poor overall product properties.
It is during the heating stage that grain size increases continuously.
The modulus of elasticity or Young’s modulus is calculated using the experimentally determined resonant frequency [18] and the values were found to be consistent regardless of the number of test performed for each samples.
As such grain size would increase due to a higher degree of grain boundary migration as compared to grain diffusion.
Two step sintering of ceramics with constant grain size, II: BaTiO3 and Ni-Cu-Zn ferrite.

After hot-rolling these steels has austenitic structure with dynamically recovered grains and with small metadynamically and statically recrystallized grains that are located on a border of elongated grains of austenite. 1.
The average size of the austenite grains is 15-20 μm (Fig. 2c).
Static and metadynamic recrystallized grains are located mainly on the boundary of dynamic and static recovered elongated austenite grains, often localised on the boundaries of the twins (Fig. 2f).
Static and metadynamic recrystallized grains are located mainly on the boundaries of the elongated austenite grains dynamic and static recovered, often placed on the twin borders.
Acknowledgements Project was founded by the National Science Centre based on the decision number DEC-2012/05/B/ST8/00149.

Control of deformation by rolling passes, number of passes, duration between passes and temperature profile of hot rolling on the basis of IDT production principles allow implementation in real industrial situation as a new method of fine grain structure formation.
Fine grain structure of steel described as austenitic grain size after product plastic deformation during recrystallization thermal deformation cycling and γ → α transformation during immediate quenching to martensite, varies according to the velocity of high temperature pressure treatment such as hot rolling for example.
Martenisitic crystal groups comprise the primary grain structure.
The characteristic sizes of martensite crystals are approximately equal to sizes of groups and to grain sizes.
This case positively changes the role of carbide formations, also, as a whole of alloying with the carbide-forming elements, since by the dispersion of microstructure actually achieves favorable redistribution between the number and the boundaries of the grains as the solidsolution concentrations of highly effective alloying elements (chromium, molybdenum, tungsten, vanadium and others), so the particles of their carbonitrides.

Irregular shape of abrasive grain top and a large number of small fragments have been observed from figure 3(a).
The whole abrasive grains appear broken wear.
In contrast, the shape of zirconia abrasive grain top is relative regular, but lamellar wear trace is found on the top of abrasive grain (as shown figure 3(b)).
This is because a single abrasive grain is actually composed of many thin hard Al2O3 layer and relatively soft ZrO2 layer, so the toughness of abrasive grain is good.
From figure 3(c) we can know that the ceramic abrasive grain tip is relatively flat, but in fact it is composed of a large number of contour and smaller micro cutting edges.

The size of the precipitates became larger and the number became smaller as the tempering temperature increased.
The width of sub-grain after tempering at 650˚C and 730˚C were about 0.35μm and 0.4μm, respectively.
It is obvious that the width of sub-grain increases with the increasing tempering temperature.
The athermal yield stress of sub-grain boundary calculated to judge the contribution of microstructure to strengthening is in inverse proportion to the average size of the sub-grains, and the sub-grain boundary is of the maximum athermal yield stress among other strengthening means [4].
So, 403Nb steel after NT650 also could be strengthened by small sub-grains.

After the SURP treatment, a 330 μm thickness of plastic deformation layer is formed on the sample surface, which indicates that a large number of defects such as dislocations are generated and the grains of the depth about 10 μm from surface are greatly refined to nanometer size [26].
For the reason that the number of grain boundaries and defects on the surface of the SURP specimens is obviously increased.
In some surface nanocrystallization processes, the increase in the number of grain boundaries and defects may lead to acceleration of the carburizing process, but this depends on the grain boundary angle, defect type, and its arrangement [30-31].
In this work, the SURP greatly refines the grain size on the surface of the samples and increases the number of grain boundaries and defects, however, due to the consistency of the rolling direction, the arrangement of grains and defects is fixed and it is at an angle to the shortest path of carbon diffusion.
In addition, a large number of grain boundaries and defects on the surface of the specimens become “traps”, resulting in the enrichment of carbon atoms decrease of carbon potential[32].According to the reference [33], the effect of surface strengthening reduces with the surface roughness of the samples decreasing[33].

The number of twins increase with the increase of rolling temperature, which conflicts with the fact that twinning takes place at lower temperature.
These fine grains are composed of fine DRX grains and many intersected twins which are hard recognizable due to the intensive twins.
However, the twins are much more obvious due to less number of twins.
The fraction of DRX grains decreased with the increasing of rolling temperature.
Therefore, many fine DRX grains other than twins were found in the A sample.

Nano-particles co-deposited into Ni-W-P alloy can inhabit the grains growth, increase microhadness and high temperature oxidation resistance during the course of heat treatment.
When increased to 400℃, there appeared a large number of Ni3P alloy phase and Ni2P, Ni5P2 metastable phases, showing that it had turned into crystalline state.
Between Ni2P, Ni5P2 and Ni3P alloy phases, Ni/P atomic ratio from low to high is as follows: Ni2P→Ni5P2→Ni3P, displaying that the stability of crystallization phase is closely related with valence number and bonding state of P.
While when increased to 400℃, the lattice distortion aggravates and a great number of Ni3P alloy phases precipitate from the structure, which is an intermetallic compound and possesses higher microhardness and has the precipitation-hardening effects, therefore, the microhardness reaches the highest value.
On the other hand, According to Hall-Petch formula, the microhardness is inversely proportional to grain sizes[9], when heat treatment temperature is higher, the average grain sizes increase, so the microhardness decrease.

After ECAE processing, the samples have fine and equiaxed grains.
Number of processing 1st 2nd 3rd 4th Specimen rotation ( o ) - 180 90 180 Extrusion rate (mm/s) 0.11~0.35 0.14~0.38 0.14~0.37 0.25~0.67 Extrusion temperature (K) 523K Results and Discussion Microstructures of 4-pass-ECAE Specimens.
The 4-pass ECAE specimens exhibit fine and equiaxed grains.
The average grain size of AZ31 and ZK31 alloys are 2.6 and 0.9 µm, respectively.
Koike et al. [5] reported that non-basal slip and grain boundary sliding could occur even at room temperature when the specimen has a fine grain size less than 8 µm.