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No Sample code Milling time Crystallite size (nm) 1 HA-10min 10 min 24.94 2 HA- 20min 20 min 23.81 3 HA-30min 30 min 23.03 4 HA-2h 2 h 22.34 5 HA-6h 6 h 20.41 6 HA-10h 10 h 18.32 A dislocation cell structure forms in the early stages of the ball-milling, which subsequently creates the low-angle grain boundaries.
As the processing time progresses, this structure transformed to fully nanocrystalline with completely random orientation of neighboring grains, which were separated by high-angle grain boundaries.
Thus, grain size decreases continuously with an increase in milling time until a saturation is reached [18].
Also, the number of dislocations introduced increases, causing an increase in the lattice strain.

This is explained by increasing of the number of thermally excited electrons.
The high frequency semi-circle (1 to 4 kHz) may be associated to electrical charge transport in the grains and the low frequency one (around 20 Hz) is relative to the grain boundaries.
Nyquist plots show relaxation frequencies at low (arround 30 Hz) and high frequencies (1 to 4 kHz) relatives to different transport mechanisms in the grain and grain boundaries.

After then pulse plating has received much attention for it can yield smaller grain size and evener particles distribution than direct current (DC) methods.
Pulse electroplating of Zn–Fe coatings resulted in the grain size reduction to 50 nm at Jp 0.2 A cm-2.
The grain size dimensions of the electrodeposited coatings were determined from profile line analysis by means of SPIP software.
A series of experiments on frequency, duty cycle, mean current density and time for positive and negative pulse were carried out to optimize the condictions for finer grain.
The following number expresses the duty cycle (%).

A continuous and uniform diamond film with well faceted grains is grown.
A broad size distribution (in the range of ~1-12 µm) of particles is evident, as minority were grown from the primary nucleating agents (homo-epitaxial growth of uncovered diamond grains) and most grains are secondary nucleated particles.
The spectrum contains a large band at about 1550cm-1, which suggests a large number of existences of non-diamond carbon.
Broken diamond grains and white small slices which are broken by the indenter during the indentation process are observed in Fig.7 (a), (c) and (d).

The materials were 16MnCr5 (1.7131, soft-annealed case hardening steel), 42CrMo4 (1.7225, quenched and tempered steel in untempered condition), and S700MC (1.8974, micro-alloyed fine-grained structural steel).
For the research described in this paper, the setting visible in b) was used As can be seen in Figure 3, every stroke produces two parts, which can subsequently investigated and thus the number of specimens is enlarged.
Figure 7: Microstructure of 42CrMo4 steel in the micrograph of a fine blanked specimen: undistorted microstructure from the specimen’s center at a cutting temperature TC = 23 °C a), distorted microstructure from the shear zone at a cutting temperature TC = 23 °C b), undistorted microstructure from the specimen’s center at a cutting temperature TC = 335 °C c), and distorted microstructure from the shear zone at a cutting temperature TC = 335 °C d) As can be seen in Figure 7, the microstructure of 42CrMo4 shows a big difference in grain size and homogeneity between the distorted state in the shear zone and the undistorted state in sufficient distance from the shear zone.
As S700MC is a high-alloy fine-grained steel, its microstructure has already before the fine blanking process a high dislocation density and thus high hardness.
The part shows a visible grain refinement, distortion and densification near the shear zone.

A new algorithm called parallel multi-objective genetic algorithm(PMGA) is developed using the coarse-grained parallel programming model with the support of MPI.
The number of the cascade channel mesh is 11264.
The optimized nerve cell number of the inter-layer is 31,and the optimum structure of the ANN is 8-16-15-3.
Fig.3 Geometry of the optimized and initial cascade airfoil The Mach number distributions are obtained and shown in Fig.4 and Fig.5.
So the Mach number of the flow in front of the normal shock descends and the total pressure recovery coefficient increases.

Nowadays the method of air current comminution, atomizing, is a acknowledged mechanical comminution means that can gain the finest grains.
(2) Where is a dimensionless number, a control variable of selecting pressure- gradient conversion method.
Fig.8 The velocity distributions of quadric accelerating jet nozzle Fig.9 The Mach number distributions of quadric accelerating jet nozzle Fig.10 The pressure distributions of quadric accelerating jet nozzle Fig.11 The outlet velocity distributions of quadric accelerating jet nozzle The other’s parameters: L11 is 4mm.
According to the comparison of two simulations, the outlet velocity, Much number of quadric accelerating jet nozzle are bigger than the linear accelerating jet nozzle’s.
Then the outlet Mach number gets bigger.

The structure grain boundary becomes more and more blur from inside to outside of the wall.
Table 1 Chemical composition of 30CrMo-M % Batch number C Si Mn P S Cr Mo 090106 0.30 0.24 0.60 0.012 0.003 0.91 0.18 090203 0.29 0.27 0.67 0.010 0.005 0.90 0.18 Test Method.
It can be seen from the diagram that the grain boundary becomes more and more blur from inside to outside.
The structure grain boundary is more and more blur from inside to outside along the wall thickness direction.

These precipitation phases in the grain matrix are the main age hardening mechanism.
This concept restricts the number of metal alloys that can be studied, such as iron, copper, aluminum, magnesium, tin or titanium.
In addition, the precipitation of AlNi phase in the matrix dendrites became larger and globular shape inside the grain matrix.
However, since the morphology do not show the Cr5Fe6Mn8 phase (σ-phase), the compound is finer grain.
These precipitation phases in the grain matrix are the main age hardening mechanism.

Set up nodal value of the chain table (-1,-16,-2 ) to show the initial front table; ③Number of balls: n=0; (2) Generate balls at each time step ① Randomly generate the radius of the ball; ② If the node is added in the first layer; If n=0, then: <1> set the value of b as the value of head pointer of the front chain table; <2> calculate the coordinate position of generated balls on the basis of b and left boundary according to the requirement of ball contact; <3> Insert n element after the node numbered as -1; Otherwise: <1> set the value of b as the value of the node whose number is the next one after the present number of balls in the front chain table; <2> calculate the coordinate position of generated balls on the basis of b and the present ball; <3> if there is no out of boundary after adding this ball, then: insert element n after the node of the present number of balls (no need to examine whether it overlaps with the prior ball) ; Otherwise: get the position
of the ball on the basis of right boundary and the present ball, insert the node, delete the node of lower boundary, the number of nodes =-1; ③ If this is not the first layer addition; Find the node and calculate the position of the ball; Judge whether it overlaps with the prior ball.
Discrete element simulation of an assembly of irregularly shaped grains: quantitative comparison with experiments[C].