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Iterative Taguchi Analysis: Optimizing the Grain Boundary Carbide in Hadfield steel Sh.
Carbides generally develop on grain boundaries and between dendrites.
Formation of these carbides between austenite grain boundaries will minimize impact strength of said steel [11].
Taguchi method incorporate orthogonal arrays to minimize the number of experiments required to achieve a given set of performance characteristics [12,13].
Table (4) Response table for Taguchi DOE Experiments Carbide content (Volume Percent) Carbide type 1 42% Fiber, disperse in grain boundary, inter granular 2 30% Fiber, disperse in grain boundary, inter granular 3 13% Very fine and disperse 4 24% Fiber, disperse in grain boundary 5 15% Fiber, disperse in grain boundary 6 8% Very fine and disperse 7 18% Fiber, disperse in grain boundary 8 12% Fiber, disperse in grain boundary 9 5% Fiber, disperse in grain boundary Figure (1) The microstructure of 9 experiments Figure 2 shows the linear graphs of the main effects and their variation between levels of parameters on the grain boundary carbide content.

This may be seen in Fig.1 where the nucleation of grain number Three was not obvious until about the 12 min. mark.
In general this behavior was observed for all grains with the exception of the grain designated number Four.
The grain number Four data shown in Fig. 2 was anomalous in that there did not appear to be a rate change when the temperature was raised from 150° C to 160° C and all growth ceased before the temperature was lowered back to 150° C.
Only grains numbered One and Seven were similar in most respects except for the initial velocity.
The apparent activation energies from the three grains that could be analyzed were 119, 127 and 143 kJ/mol for grains numbered Two, Three and Six respectively.

Because of the increased number of grain boundaries the motion of dislocations is hindered.
During solidification ultrasound can cause a reduction in grain size, the columnar equiaxed transition and/ or a more homogeneous grain structure.
The grain sizes of samples have been determined.
Figure 2 shows measured grain sizes against the amplitudes.
b) The shorter the solidification times the smaller the grain size.

In Fig. 3 (a), after 1 pass deformation, the microstructure still retained a large number of coarse original grains, which contained a densely distributed fine-lamellar LPSO phase with uneven grain size.
There were a large number of fine grains, which were typical DRXed grains.
A large number of LAGBs were also distributed in the grains of the fine grain region, indicating that the DRXed grains were also gradually refined.
With the increase of deformation, the blue points increased, indicating that the number of the DRXed grains increased.
It can be inferred that with the increase of processing passes, the number of unDRXed grains decreased while the number of DRXed grains increased.

If a misorientation of few units of degrees is allowed in each grain, the total number of grains in the explored area has been calculated to be around 2.4∗10 3 and 2.2∗10 3 for sample A and B, respectively.
Moreover, the grains are preferentially oriented so that the ϕ2 values are strongly peaked on 0o and 180 o while the φ for most of the grains has two peaks around 30 o and 150 o .
In this specific case, each grain possesses a strongly anisotropic CTE.
The thermal expansion coefficient is a second rank symmetric tensor, in which the number of independent components is linked to the crystal symmetry of the material.
The grain orientation distribution in the two films has been studied by means of electron diffraction.

The size of liquid droplets was increased while the number of liquid droplets was decreased with increasing the isothermal holding temperature and time.
Additionally, with the increase of isothermal holding temperature, the liquid film becomes more and more thicker, and the number of adjacent grains will be decreased.
Therefore, the size of liquid droplets is increased while the number of liquid droplets is decreased with increasing the isothermal holding temperature and time.
Coarsening kinetics of solid grain.
Meanwhile, the size of liquid droplets is increased while the number of liquid droplets is decreased with increasing the isothermal holding temperature and time

Generation and motion of high angle grain boundaries are necessary to remove the deformed grains.
When a particle contacts the grain boundary and its surface replaces part of the grain boundary, the energy of the grain boundary is decreased.
dislocations due to their high number density and high thermal stability.
Consequently, both the nucleation and growth of recrystallized grains were retarded during solution heat treatment in the case of small a-dispersoids with high number density.
It was found that Mn could strongly affect the morphology and number density of the dispersoids.

As seen in the OIM maps, after the first pass, the as-casted microstructure is stretched into fibrous structures, but it still has some residual coarse grains as illustrated a dark area and mark as G in the Fig 3a where a large number of LAG are found.
After two passes, the coarse grains are divided into fine equiaxed grains (~ 5μm) that are surrounded by HABs, and no residual coarse grain is found in the entire region.
Unlike the process at low speed, even after the first pass of Conform process, the well-developed sub-grain boundaries with small number of tangled dislocations are produced (see Fig. 4a), indicating that recrystallization happened during initial passes at high speed.
Moreover, a large number of precipitates are observed in the Fig. 4(c)-(f).
And the number of new recrystallization grains with straight grain boundary (see Fig. 6(d) and (e)) increases, which can be postulated that the continuous dynamic recrystallization induced by strain may occurred and cause the grain refinement, which may be another reason for the rising of the YS and the ductility.

In wheat grains, the levels of Pb and Cd were 50 times and 8 times of the limited values of hygienic standard for grain respectively, while Cu and Zn concentrations did not surpass the standard value.
It suggested that Cu and Zn concentrations in wheat grains were in the safe interval.
To be concerned that the average concentrations of Pb and Cd in wheat grains were 50 and 8 times of permissible limits (GB 2715-2005) respectively, signifying the severe pollution of Pb and Cd in wheat grains.
There was no significant correlation between Cu concentration in wheat grains with that of the other metals, thus, the source of Cu in wheat grains needed further investigation.
Heavy metals in wheat grain: assessment of potential health risk for inhabitants in Kunshan, China.

Complete suppression of typical columnar grain growth and significant equiaxed grain refinement is observed.
Achieving a fine and equiaxed grain structure, whilst preventing cracks and hot tearing, is typically achieved by chemical grain refinement.
Casting Shearing speed (rpm) Avg. primary α–Al grain size (µm) Avg.
Such oxides may act as substrates for nucleation but are not effective for grain refinement due to their poor wettability and low number density.
· Formation of coarse dendritic α–Al grains is completely suppressed and significantly refined grains are promoted under intensive melt shearing