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The scanning electron micrograph results reveal different grain shapes and sizes and also different grain growth rate during welding.
The first group of EWP-D and EWP-H contains round and equiaxed grains.
It can be seen that the grains at the balled region are very large, i.e. in EWP-E electrode, the cross-section is almost consumed by one very large grain.
The ability to control the grain growth rate and keep grain size small especially within the balled end is crucial in determining the quality in term of the endurance of the tungsten electrode used.
Acknowledgments The author would like to thank National Metal and Materials Technology Center (MTEC), Thailand for financial support (project number P1550713), equipment and facility used in this research.

The properties of welded joint will been improved by these fine crystal grain.
Following the increasing of magnetic field current, the number of α-Mg is increasing and display as equiaxed grain, the β-Al12 Mg17 is diffusion distribution at the grain boundary of α-Mg.
The grain consist of coars α-Mg and series β-Al12 Mg17.
These broken crystal grains can refine grain and improve the properties of welded joint.
The properties of welded joint will be improved by these fine crystal grain.

Temperature variations Grain size statistics Local compositional changes?
Temperature variations Grain size effects.
The influence of grain size statistics depends upon the number of diffracting grains within the sampling or gauge volume.
From this information one can assess whether grain size will pose a problem.
Oscillating the specimen will increase the effective number of grains 'seen' on the detector.

After machining, samples of 5x5 mm were sectioned by wire-EDM, then polished and etched for 35 seconds using Kalling’s reagent (number 2) to observe microstructural changes (affected layer and grain size) using a light optical microscope (1000X).
Affected Layer and Grain Size.
The grain size of each machined surface has been measured by optical microscope (1000X), and it was found that in all investigated cases the grain refinement occurs.
Grain size on the bulk material Grain size on the bulk material (a) (b) Figure 6: Grain size evolution from the machined surface to the bulk material (a) different cutting speeds at 0.1 mm/rev as feed rate and for (b) different feed rates at 70 m/min as cutting speed.
According to Herbert et al. [8] different intensity represents different grain size.

But the alloys commonly used for thixoforming are limited to a few casting alloys and only a limited number of trial have been carried out on wrought alloys.
One coarsening mechanism is the coalescence of the grains, joining together and leaving an entrapped liquid pool in between the two grains.
Another grain coarsening mechanism is likely to be the ripening [4], in which the large grains grow and the small ones remelt.
The grains grow and turn into globular ones through the movement of the grain boundaries.
When the specimens were reheated at 609℃ and 622℃ for 0-30min, the average grain size of grains was 106-124㎛ and 82-91㎛, respectively.

In case of a two-phase ceramic composite [1–13] the number of unknown material and interfacial constants, that have to be calibrated experimentally, increases rapidly [14, 15].
The only material parameters in this model are two Lame constants for each phase and two damage constants, both for the bulk grain and the grain boundary.
Lowering the limit strain for the grain boundary (force between two points that belong to different grains) mimics a weak GB and privileges intergranular fracture.
Further damage propagates mainly through grain boundaries.
Acknowledgement This work was financially supported by Ministry of Science and Higher Education within the statutory research number S/20/2015.

And the deposition current efficiency is reduced by 10%, the hydrogen evolution in cathode cause the coating surface a large number of cracks, defects and so on.
A large number of experiments on the amorphous alloys have shown that this composition is in a high surface free energy and a good chemical activity [8.9].
Effects on the deposits microstructure and grain size.
Using Jade software to fit the finishing crystalline line, calculate grain size, analyze phase structure of the deposits coating, the results of the amorphous content, grain size, phase composition in each deposit alloy are shown in table 2.
The grain size is about 34.3nm by Scherrer calculation.

The sintering behavior of powder compacts was investigated by evaluating the densification, the lattice constant c for AlN, and the dihedral angle of the interface between the AlN grains and the grain boundary liquid-phase.
Furthermore, it changes the grain-boundary phase to Y4Al2O9→YAlO3→Y3Al5O12 while it traps oxygen inside the AlN grain, promoting purification of the AlN.
AlN Al VOAlOAl ⋅⋅⋅ +'+→ 3232 (1) These point defects generate a stacking fault with a coordination number of 6, with a smaller lattice constant than the AlN stacking with its coordination number of 4.
The wettability of AlN grains with a grain-boundary phase was improved by the presence of a solid solution of oxygen in the AlN lattice as discussed below.
Consistent with this trend, the wettability of the AlN grains by the liquid phase was worse with the elimination of oxygen from AlN grains.

Still, the fraction of recrystallized grains is very small and no significant grain refinement takes place.
Grain size is rather homogeneous, although still some large initial grains remain present.
It can be seen that no twinning takes place clearly in all the grains; recrystallized grains are visible along some grain boundary areas.
The average grain size of the small grains is about 3μm (see Fig.4d).
The smaller grain size observed in the sample with 2.38 effective strain in comparison with that with 2.07 effective strain is attributed to the larger number of dislocations generated in the former due to the larger strain imposed.

This ultra-precision magnetic abrasive slurry is made by simply mixing the super-minute abrasive grains, super-minute globular iron particles, and oily grinding liquid.
The UMAS is produced by mixing simply the super-minute abrasive grains, super-minute globular iron particles, and oily grinding liquid.
The vibration frequency can be adjusted by controlling the number of revolutions of the motor through an inverter.
To the experiment of each rotation speed, finishing time was set up so that the number of rotations might become equal.
The UMAS simply mixed super-minute abrasive grains, super-minute globular iron particles, and oily grinding liquid.