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Furthermore, research on 3D microstructure simulation with many grains in large-scale is scarcely reported.
In 3D simulation, the homogeneous temperature field assumption was induced for each grain domain.
Fig.3 (c) and (d) shows the multi-grain growth procedure in gradient temperature field.
As the cooling rate increased, the grain size decresed.
(a) (c) Fig.6 3D simulation results of 719 grains (a) grain morphology and distribution, (b) solute distribution Tab.1 2D and 3D calculation time of the simplified CA model Type Cell Number Nucleus Number Computing Time (min) 2D 100×100 12 11 2D 500×500 100 95 3D 100×100×100 50 8 3D 200×200×200 719 70 Summary A simplified CA model was developed for simulating the micrustructures of Mg alloy.

The wear tests showed that the wear weight loss curve of Hadfield steel will be bent down after some critical impact numbers.
The wear curve of the AISI 1045 steel, however, shows a step-like characteristic with increasing impact numbers.
Grain size of ferrite is about 10~12 µm.
Finally, nano grains are formed in subsurface.
The "white layer" with nano grains does not.

The normal DC casting has coarse grain, of which the edge is a small dendrite spacing with tiny dendrite arms, but the mixed crystal structure composed of coarse dendritic phase and fine crystal grains appears in the center.
The average grain size distribution on the cross section of the ingot is shown in Fig. 4.
The grain size of the normal DC casting gradually increases from 308μm at the edge to 470μm at the center.
The average grain size of the ingots applying the homodromous electromagnetic fields increases rapidly in the radial direction, and the average grain size of the ingots to which the reverse electromagnetic fields are applied remains between 149μm and 223μm.
It leads to inhibit dendrite growth, increase the number of crystal nuclei, promote the production of equiaxed grains, and refine grain.

It was observed that the grain sizes increases appreciably.
It is important to note that grain characteristics are controlled to produce different mechanical properties.
Generally, the faster the cooling rate, the refined and smaller the grain sizes will be but in this instance, the rate of cooling was kept constant but varied the number of scan irradiation and the laser power.
Table : Measured grains of the parent and the LBF components No.
The number of scan irradiation being the number of time the laser passes on the surface of the component.

As the number of cycle increases, the hysteresis loop transforms to a near linear elastic response.
Such monitoring was carried out for the condition of 100CF at different cycle numbers.
In Fig. 6 (a), the grain boundary offset height measurements vs. the number of cycle are given, showing that offset increases monotonically with cycle number.
The cyclic creep observed was found to increase with the number of cycles, which is associated with the grain rotation. 3.
Crack was verified to nucleate at grain boundaries as the result of severe grain rotation.

The anisotropy of the individual crystals, however, is smoothed out only in the presence of a large number of grains having a random distribution of orientations.
Its magnitude depends upon the statistical distribution of grain orientations – the "crystallographic texture" or, more simply, the texture.
Local variations in texture, as well as the arrangements and types of grain/phase boundaries, may give rise to inhomogeneous material properties.

Processing by HPT is proven to improve the mechanical properties and microstructural behavior of materials by refining the grain size to ultrafine grains [11-15].
This processing route is proven to cause equiaxed ultrafine grains having high angle grain boundaries [23].
High-angle grain boundaries denote misorientations across the interface of 15° or more and the low-angle grain boundaries are defined as measurements having misorientations between 2° to 15°.
The average grain size of the Al-7075 disk processed by HPT through a total number of 5 turns was ~ 250 nm in the center and ~ 500 nm around the peripheral regions as reported earlier [26].
These curves are typical of ultrafine grained materials at high temperatures.

CWHEs design is some number of tubes are welded together and coiled.
It was noted that on the inner surface, grain boundaries are roughly etched, that could be associated with carbides along grain boundaries that lower its corrosion resistance.
Along the grain boundaries, carbides were etched on the inner surface’s tubes.
The depleted layer can extend a number of microns in depth and would seriously degrade corrosion resistance if not removed.
Along the grain boundaries, carbides were etched on the inner surface’s tubes.

The paper presents the abrasive grain motion equations, removal rate model,grinding force model and grinding force ratio model.According to the grinding force model, the grinding force will decrease as the spindle speed, vibration amplitude and vibration frequency increase.
The kinematics analysis of UAG Fig. 1 The motion model of axial ultrasonic vibration assisted grinding [2] As shown in Fig. 1, there arethree kinds of grain motion such as grinding wheel rotational circular motion,grinding wheel feed movement and the simple harmonic oscillation.Based on the UAG kinematics analysis, establish the single abrasive grain trajectory model.
x=(vw+vs)t1 (1) y=Asin(2πft1+Ø0) (2) z =R-Rcosωt1 (3) Wherevs is grinding wheel speed,t1 is grinding time of single grain, ω is grinding wheel angular velocity, vw is feed rate,f is ultrasonic frequency, R is grinding wheel radius, Ø0 is ultrasonic vibration initial phase, A is ultrasonic amplitude.According to the single abrasive grain trajectory model can get the grain trajectory curve: Fig. 2 (a) (b) (a) Grain trajectory in single rotation period of grinding wheel (b) The trajectory of single grain contact with the workpiece Assume the ultrasonic vibration initial phaseØ0=0, the trajectory length of single grain contact with material in single rotation period can be defined as follow: (4) UAG material removal rate modeling Fig. 3 Abrasive grain pressed depth Fig.3 shows pressed depth of single abrasive grain.
The depth of grain pressed into the material is ag, cone apex angle is θ, and the grain trajectory groove width Ø can be deduced as follow: (5) The cross sectional area of grain pressed into the material can be found: (6) Single grain material removal volume is defined as follow: (7) Assume that the distributing density of the dynamic grain on the wheel surface is Nds，the grain number through the dynamic grinding area in unit time is N=Ndsbvs，Whole material removal for volume in unit time can be defined as follow: (8) The average chip cross section area in AUAG is: (9) Average grain pressed depth is: (10) The grinding force modeling of UAG Fig.4 Grinding force distribution of single grain The grinding force produced by chip deformation As Fig.4 shows, agis grain average cutting depth.There is an angle Øbetweengrinding direction and OAB .The area of OAB is ds.Grinding forcedF is vertical to the conical surface
Thenwe can deduce: (12) ρis cone length, can be found: (13) Put (13) into (12),can be obtained: (14) Substitute (14) into (11),can be found: ; (15) The grinding forceof single grain: ; (16) The total grinding force: ;

The heat is inversely proportional with the alloy grain sizes.
Introduction For thousands of years the development of practical alloy systems has been based mainly on one principal element as the matrix, as in iron-based, copper-based, and aluminum-based alloys, limiting the number of applicable alloy systems, even though a substantial amount of other elements is incorporated for property/processing enhancement [1,2].
The fusion zone grain size is less than elsewhere, from the Fig.
Fig.5 Sample 5 after Welding Dendritic grain size is shown in Fig.6. a and b are the grain size of horizontal and vertical, respectively.
Four samples grain size were measured and draw the diagram of grain size versus heat, as shown in Fig.7(a) and Fig7(b).