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As the number of multilayers increases, the surface roughness decreases to 22.5 nm at CCN120.
The lower roughness of TiC/TiCN multilayer is attributed to the grain refinement that results from the extremely thin multilayer deposition sequence.
Fig. 4 Surface roughness (Rrms) as a function Fig. 5 Critical load (Lc) as a function of the of the number of TiC/TiCN multilayers number of TiC/TiCN multilayers Nanohardness and Elastic modulus.
The Hall-Petch relationship that relates the grain size of a polycrystalline material to its mechanical properties has been known for many systems [7].
Therefore, the nanohardness of multilayers can be said to greatly affected by grain refinements, and only slightly affected by the elastic modulus.

By changing the sample position, tests at different number of cycles can be performed on the same specimen.
Prior austenite grain size was observed in samples etched by immersion in Van Giesson picral solution, plus 2 ml of wetting agent Teepol and 2 drops of HCl for 5 minutes, followed by final polishing with Buehler’s Mastermet 2.
The prior austenite grain size was around 15 mm and the sample was formed of martensite, retained austenite (16%) and cementite (3-4%).
It is expected that once sufficient amount of test data is collected, it will be possible to correlate the inclusion depth, their minimum size and shape factors with the crack initiation process much easier than through conventional testing. 104 5μm 5μm 5μm 65 mm 250 mm 570 mm 106 5μm 5μm 5μm 110 mm 280 mm 445 mm 4.5 * 107 5μm 5μm 5μm 160 mm 280 mm 373 mm Figure 3 Cracks after one-point bending testing (a) number of cycles = 104 (b) number of cycles = 106 and (c) number of cycles = 4.5 * 107.
From Fig. 3, it can be concluded that the higher the number of cycles, the longer the cracks.

Cracks were observed in certain areas with the formation of stray grains.
The coatings should be single crystal to eliminate the diffusion short circuit through grain boundaries.
The formation of stray grains in Figure 1 was probably caused by the quality of the substrate.
Figure 3 OIM (image quality map) showing strain grain formation close to the substrate/spark deposited layer interface.
Chen,  Advanced Science Letters, Volume 4, Number 3, March 2011 , pp. 996-1001(6)

Research data show grain refinement makes the surface harder.
SEM-images provide evidence that all melted zones consist of uniaxial grains α-Mg with a high density of inter-grain boundaries.
Grains are 2.30 µm to 4.87 µm on average.
Apparently, an average grain size α-Mg increases at higher laser energy densities.
Therefore, a coarse grain is formed in a melting area at lower speeds of cooling.

The MPT63 (finer grains) exhibited higher strain than MPT66 (coarser grains) in both directions.
SELFPOLY-7 accounts for the effects of crystallographic texture and grain shape, but not grain size.
There are a number of alternative explanations for this: 1.
The grain morphology is different amongst the three materials, the FS having a coarser grain structure, while the MPT materials have more elongated grain structures.
This suggests an effect of grain size.

The production of ultrafine-grained metals through severe plastic deformation (SPD) has attracted significant interest in the scientific community due to the improvement in mechanical properties.
High-pressure torsion (HPT) [3] is an SPD technique especially effective in the fabrication of ultrafine-grained materials with grain sizes in the nanometer range.
Although there are many reports using finite element modeling (FEM) to examine the flow process in HPT [4,8-10], a limited number of studies has been conducted concerning the compression stage in HPT processing [11].
Langdon, Advances in ultrafine-grained materials, Mater.
Kim, Nanoindentation analysis for local properties of ultrafine grained copper processed by high pressure torsion, J.

The self-affine correlation length is found to be related to the grain size resulting from the refining and modifying treatments applied to the alloy.
With the purpose of assesing the influence of the modification and refinement treatments on the microstructural parameters and the morphology of the fracture surfaces, the grain size and the secondary dendritic arm spacing (SDAS) were measured using image analysis algorithms.
The fractographic analysis shows that the ascast specimen contains a larger number of secondary cracks, a fact possibly due to the greater amount of the Al15(MnFe)3Si2 phase compared to the modified specimen.
These values clearly correspond to the grain sizes reported above.
On the other hand, the correlation length was found to correspond to the grain size, implying that this selfaffine parameter is sensitive to the refining treatment of the aluminum alloy under study.

It was shown, that the formation of MoSi2 proceeds by two different mechanisms and accordingly, two types of microstructures are formed: (i) a compact layer (usually with expressed columnar structure) by the reaction diffusion mechanism; and (ii) separated fine grains by crystallization in the volume of saturated Me-Si melt.
Meanwhile, for a number of high-temperature processes such as Self-propagating High-temperature Synthesis (SHS) or combustion synthesis [1,2] just these temperatures are very important, when silicon is present as a melt.
After a certain time, the whole disilicide zone becomes bilayer and consist of a compact diffusive layer and the zone of grains, formed by crystallization from saturated melt (Fig.1e).
columnar structure) by the reaction diffusion mechanism; and (ii) separated fine grains by crystallization in the volume of saturated Me-Si melt.
The appearance of disilicide grains within the melt indicates that they were formed by crystallization.

SEM micrographs showed the grain size decreased when the S content increased.
Grain size and surface morphology were revealed in accordance to scanning electron microscopy (SEM).
From the surface view, it can be seen that the grain size decreased as the composition (x) increased.
Acknowledgments This work is supported by King Mongkut’s Institute of Technology Ladkrabang under grant number A118-59-038.

Cracks were observed in certain areas with the formation of stray grains.
The coatings should be single crystal to eliminate the diffusion short circuit through grain boundaries.
The formation of stray grains in Figure 1 was probably caused by the quality of the substrate.
Figure 3 OIM (image quality map) showing strain grain formation close to the substrate/spark deposited layer interface.
Chen, Advanced Science Letters, Volume 4, Number 3, March 2011 , pp. 996-1001(6)