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For polycrystalline materials, for example the grain corners can act as preferred nucleation sites.
stress, MPa average grain diameter, μm 0.30 59.4±3 0.50 57.9±3 0.90 56.4±3 1.20 54.8±3 Table 2 The average grain diameter of Fe-2.96 at.% Ni specimens under various compressive stresses during the g®a transformation[15].
The average grain size of all initial specimens is 65.7±3 μm.
The nucleus density is estimated from the number of product grains, assuming that (only) one nucleus is the origin of each product grain; thus N*=.
It is experimentally very difficult to measure the grain size of the austenite at high temperature.

The columnar region consists of elongated grains with a preferred orientation.
In the single phase region (2), from 1.5cm large grain growth occurred upon heating.
Beyond 5.4 cm (7) the morphology of the growing grain structure was equiaxed.
Those models can predict grain structure and CET.
Acknowledgements This work is financially supported by European Commission (contract number NMP-CT-2004500635) Sixth Framework Programme, as the project is co-funded and coordinated by the European Space Agency.

Step length of the discrete model is △x, △y and △z in ε direction, y direction and z direction respectively, therefore the position of model can be represented in a discrete form: ( ) ( ) ( ) ],0[, ;],0[, ;],0[, z y x NkkzkzNjkyjyNikxi ∈∆⋅= ∈∆⋅= ∈∆⋅=ε (5) where N is the number of steps.
A is the overall wear flat area, and the subscripts g and w represent grain and workpiece, respectively.
Thermal physical properties of CFRP and SiC grain on the wheel are presented in Table 1.
The grinding conditions, grain characteristics and boundary condition are presented in Table 2.
The depth of thermocouple beneath surface was estimated by the wheel depth of cut and the number of passes before thermocouple exposed itself on the grinding surface.

The BiFeO3 crystal grains were clear.
Moreover, the obvious BiFeO3 crystal grains could not be seen.
The crystal grains size was much smaller.
There were a large number of space charges, which was unfavorable for the electric domain to grow up.
From Fig. 3(b), in the low frequency, BiFeO3 thin films prepared at 500 °C and 550 °C annealing had the very high dielectric loss due to the large number of space charges.

This can be attributed to the grain refinement due to stirring.
However, comparing to the grain structure of the stir zone, coarse grain structure was observed in the material flowed into the screw hole.
No change in grain structure of SS400 has been observed.
Increasing the number of screw holes or traversing the tool along the center line of the screw hole would be another possible method for improving the strength of the interlock.
Increasing the number of screw holes or traversing the tool along the center line of the screw hole. 3.

σx= σhomogeneous deformation+σfriction+σadditional deformation+σbearing (3) In a multi-stage process, the sequence design or draft will be constituted by a number of consecutive stages (n) and the current stage is defined as i.
Besides, the Hall-Petch Equation (10) allows to predict the grain size in a metal that has been plastically deformed [26].
Summary of results from the FEM and analytical models and grain size calculation.
Modelling of grain size evolution with different approaches via FEM when hard machining of AISI 4140.
Six decades of the Hall–Petch effect – a survey of grain-size strengthening studies on pure metals.

The large triangular faceted diamond grains may have great contribution to the adhesive strength between the Journal Title and Volume Number (to be inserted by the publisher) 855 film and the substrate, but unfortunately they form a rougher surface with high friction coefficient.
Fig.6 shows the curves of surface roughness with the number of holes and Fig.7 shows the signals of cutting torque and thrust during drilling the 10th hole with the different drills.
The initial load impact to the workpiece was the main reason for initial acute attrition due to the lost diamond grains at the local cutting edge, especially at the corner point, as seen in Fig.8b.
Conventional coated drill Fz M Torque M/N.cm Thrust Fz/N Fig.6 Surface roughness of workpiece with the number of holes 0 2 4 6 8 10 12 3 4 5 6 7 8 9 10 11 Surface roughness Ra (¦Ì m) Number of holes Uncoated drill Conventional coated drill Multiple coated drill Fig.5 Values of abrasion width of outer cutting edge corner with the number of holes 0 2 4 6 8 10 12 14 16 18 0.00 0.02 0.04 0.06 0.08 0.10 0.12 Abrasion width of outer edge corner (mm) Number of holes Uncoated drill Conventional coated drill Multiple coated drill 0 0.5 1.0 1.5 2.0 2.5 3.0 -40 0 40 80 120 160 200 240 280 320 360 400 Mz (N.cm) Fz (N) Time (s) Mechanical Units DynoWare by Kistler M Fz Torque M/N.cm Thrust Fz/N a.
Uncoated drill Journal Title and Volume Number (to be inserted by the publisher) 857 yielded long tool life and stable drilling process.

The alloying elements influence the microstructure, the size of the α-Mg grains decreasing considerably. 1.
As previously noted [16], Mg-0.5Ca-xY alloys form a major phase of the α-Mg type, with grains of significant size, uniform globular compounds distributed in the metallic mass - the A-area, respectively intermetallic compounds - the B area, arranged at the boundary of the main phase grains.
The B area revealed by a light gray lamellar appearance at the Mg grains interface is attributed to Mg-Ca compounds.
Acknowledgment „This work was supported by a grant of the Romanian Ministery of Research and Innovation, CCCDI – UEFISCDI, project number PN-III-P1-1.2-PCCDI-2017-0239 / 60PCCDI 2018 , within PNCDI III”.
Xiao, Effect of Zr, Mn and Sc additions on the grain size of Mg–Gd alloy, Journal of Alloys and Compounds 470 (2009) 311–316

It consists of slightly compacted fine grained calcarenite, poorly cemented and pale-yellow coloured.
Data are reported as the average values calculated on the number of measurements made for each direction based on the size of each specimen.
As regard specimens in saturated condition, the experimental campaign is still running, thus the number of samples tested is lower compared to specimens in dry condition.
In the Lecce stone the degree of cementation is very low: the carbonate cement is not uniformly distributed, and mostly occurs at the contact between grains or in the grain walls, in open pore spaces, as a fine crust on calcite microcrystals.
The presence of water cause a detachment of the calcite grains decreasing the electrostatic bond that holds the grain together in dry condition: thus the P-wave velocity in the skeleton of the stone is reduced by the detachment of the crystal grains due to the presence of water [12] (P-wave velocity in water is less than P-wave velocity in mineral skeleton).

Introduction With the deepening of the research and application in micro electromechanical system (MEMS), an increasing number of people come to realize that problems take place by failure and reliability in MEMS.[1] The metal microstructure in MEMS usually happen to have deformation, fracture, wear and fatigue damage in working process subject to thermal power or alternating load, and cause the microstructure of failure, and lead to the failure of the whole MEMS [2].How to improve the fatigue life of these metal microstructure, wear resistance and corrosion resistance and other properties, and then improve the reliability and prolong the service life of the microstructure devices, become the key of resolving the problem [3].The effective methods to reduce failure modes including the implementation of optimization design based on the model, the operation mode and chemical surface treatment [4].
Compared with the macro components, the components of the material surface grain number in total grain number of the high percentage, of the material surface grain restriction by the surrounding grain size is small, so easy generation slip, so that the flow stress decreases, and the decrease of strength[19].
The scales, flare size and grain size in an order of magnitude, flare uniform distribution hypothesis was no longer, must consider the spatial distribution of energy.
Laser micro shot peening process, the shock wave function in several grain, within the scope of the material flow stress and hardening of microscopic scale by impact is bigger also, need to meet deformation coordination, stress condition such as balance, material plastic deformation is anisotropic and uneven, each grain internal stress distribution is uneven, and the stress field of each grain is the stress field of superposition[20].