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The Minitab parameters Factors 3 Replicates 1 Base runs 27 Total runs 27 Base blocks 1 Total blocks 1 Number of levels 3, 3, 3 One of the primary objectives of this research is to establish relationship between different control variables of grinding process and the measured parameters.
Theoretically, the more pressure between the workpiece and the grinding wheel, the deeper cutting depth of single abrasive will be, some micro-cracks may even occur on the surface of the workpiece during grinding, and the contact area between them increases, it leads to an increase of the number of effective grinding grains, so that roughness increases obviously.
Thus it increases the surface roughness as the workpieces are exposed to new grain each revolution.
Since the workpiece rotates with the spindle and moves in a circular motion, after a number of turns, the trajectory of workpiece covers the whole wheel area meaning that there are more chances for the workpiece to contact more abrasives.
When the load increases, the abrasives will be embedded deeper into the workpiece surface, which leads to an increase of the number of effective grinding grains, which improves the grinding efficiency greatly.

Aluminum alloys instead of cast iron or steel are used in a significant and increasing number of engine designs.
The selected number of oscillating strokes was 50,000, sliding velocity 70 mm/s, length of strokes 5 mm with an imposed measurement load of 10 N.
The aim is to obtain round granulates with a monomodal and narrow grain size distribution with mean grain size D50 in the range 30÷120 µm.
The powders grain sizes are given in table 1.
Three spray-dried powders possess the required properties, i.e. monomodal grain size distribution, mean grain size in the range 80 ÷ 120 µm, good flowability and round shaped grains.

Plasticity is the number of droppings for a pellet, N; durability – effort to crush a pellet, kg.
Results of reduction of iron ore pellets Sample number Reducibility (State Standard of the Russian Federation 17212-84), % Absolute (max oxidation level) Absolute (mass loss) Real Absolute reducibility of initial probe 1 63.20 60.64 62.88 0.8676 2 64.58 58.74 64.28 0.8419 3 66.14 58.91 65.86 0.8036 4 69.02 59.06 68.78 0.8098 Table 5.
Durability indicators after low-temperature reduction of iron ore pellets Sample number Grain-size fraction, mm Initial mass, g Mass after reduction, g LTD +6.3 LTD –3.15 LTD –0.5 1 16 ÷ 12 500 491.9 97.86 1.76 1.28 2 16 ÷ 12 500 487.3 97.61 1.76 1.53 3 16 ÷ 12 500 478.7 94.61 4.17 3.91 4 16 ÷ 12 500 486.8 97.10 2.17 2.03 The temperatures for softening and melting of iron ore pellets according to State Standard of the Russian Federation 26517-85 are given in Table 7.
Indicators of temperatures of softening and melting of iron ore pellets Sample number 1 2 3 4 Grain-size fraction, mm 16 ÷ 12 16 ÷ 12 16 ÷ 12 16 ÷ 12 Temperature of softening beginning, °С 1230 1230 1210 1200 Temperature of softening ending, °С 1315 1300 1290 1310 Temperature interval of softening, °С 85 70 80 110 The durability of burned iron ore pellets was defined on compression in accordance with the State Standard of the Russian Federation 24765-81.
Indicators of mechanical durability of iron ore pellets Sample number Average size of probe pellets, mm Durability of burned pellets (1200°C), kg/pellet 1 12.25 162.33 2 12.71 169.93 3 12.54 163.73 4 12.26 185.74 X-Ray Diffraction Analysis X-ray diffraction also has been carried out to study the mineralogical composition of sinter and pellets.

Zhou et al, [10] investigated the effect of deformation parameters on the recrystallized grain size of IN-718.
A number of the flow stress-strain curves obtained from the hot compression tests at different temperatures and strain rates are shown in Fig.1.
For all the three strain rates, the initial equiaxed grains with a large quantity of twin boundaries transformed to the recrystallized grains with wavy or corrugated grain boundaries; the deformed alloy completely or partially transformed to the microstructure of approximately equiaxed defect-free grains predominantly bounded by high angle boundaries.
As the strain rate increases, the average grain size of the 028 alloy became more and more refined (Fig.3c-d).
It is worth emphasizing that the microstructure of deformed alloy partially transformed to approximately equiaxed grains at a high strain rate of 1s-1(as shown in Fig3d) due to the deceasing growth time of DRX grain.

For fine-grained binary alloys, the room temperature elongation to fracture varies with Al-content, exhibiting a maximum at the two-phase composition Ti-48at%Al.
Boron is typically used as a grain refining agent.
For a large number of these 3rd generation alloys the constitution can be written as: Ti– (42 – 46) Al – (0 – 10) X –(0. – 3) Y – (0 – 1) Z – (0 – 0.5RE), (2) where, X = Cr, Mn, Nb, a; Y = Mo,W, Hf, Zr; Z = C, B, Si; RE: rare earth elements.
The aim of primary hot-working of cast ingots is to convert (or breakdown) the coarse-grained microstructure into a fine-grained and uniform microstructure suitable for subsequent wrought processing or heat treatments.
The valves have a homogeneous fine-grained microstructure and have been successfully tested in engines.

Immediately after the mechanical alloying process, the powders have grain size which can be as fine as 10nm [4].
The instrument showed the distribution was poly-dispersed due to the presence of a number of very small particles.
On the other hand XRD gives a bulk average value of grain size.
Improved mechanical properties may potentially be achieved by refinement of the grain size to nanoscale dimensions.
The nano-agglomerated particles are expected to pin the grain boundaries and prevent grain growth at high temperature e.g. 14000C for Ni based turbine blades.

This can result in inaccuracies in estimating tie-line compositions for these phases because of errors in extrapolating inadequate number of data points.
Figs. 5 and 6 show the observation of very little cumulative misorientation, i.e. less than 1 degree, within each grain of IM1 or IM3 phase across the interface.
It is means that no significant distortion or rotation happening along the grain at the interface.
The crystals in the grain grow in the directions parallel to the direction of the initial nucleus orientation.
The analysis of more than 50 pairs of the IM1 and IM3 grains orientation at the grain boundaries has shown no clear tendency in terms of their joint orientation.

The described above sintering routine allowed production of zirconia ceramics with relative density higher than 0.98-0.99 and grain size below 120 nm.
Grain size decreases to 5-20 nm after first 2.5 h of milling, to comparison, grain size in raw baddeleyite exceeds 1 um.
Phase composition (a) and mean grain size (b) as a function of dry milling time.
Acknowledgments This research was supported by the Russian Science Foundation (project number 16-19-10405).
Svancarek, Two-stage sintering of alumina with submicrometer grain size, J.

When alumina was stressed, the wave number of the R lines shifted from their stress-free values.
Elemental analysis of specimens after thermal exposure at 1100℃ for 1000h Mixed Oxide According to previous research, when the active element is close to the coating/layer interface, at a very high temperature, it would diffuse along the grain boundary [5].
According to Jedliski’s research [6], active element Y can form precipitate phase Ni5Y along the grain boundary which can be oxidized to form Y2O3.
Active element-enriched oxide can inhibit the grain growth of unstable alumina and increase the vacancy concentration of the unstable alumina.

Recently, by combining combustion synthesis with ultra-high gravity field, the solidified ceramic composites have been achieved in fine-grained microstructures through a complex coupled processing of reactive melt infiltration, liquid diffusion, mass transfer, crystal growth and so on [2], and microstructure modification, microstructure homogeneity is an important issue for improving mechanical properties of solidified TiC-TiB2 ceramic composite.
Fig.2 FESEM images of TiC-TiB2 solidified ceramics in ultrahigh-gravity field with different acceleration (a)500g (b)1000g (c)1500g (d)2000g (e)2500g Fig.3 FESEM images of TiC-TiB2 solidified ceramics in ultrahigh-gravity field with different acceleration (a)500g (b)2500g By observing Fig. 2, it can be found that the microstructure of the ceramic substrate composed by a large number of dark gray lamellar composition (TiB2), embedded in or distributed in the small amount of irregular shape of the light gray (TiC) and white tissue(Cr).
Further, when the acceleration of the high gravity field is small, the grain is relatively coarse, as shown in Figure 2(a).
With the increase in the acceleration of high gravity field, the grain size of dark gray lamellae (TiB2) decreases, that is due to the force field enhanced phase separation Stokes convection significantly[4], which strengthen oxide droplet coagulation effect and made the distribution of ceramic melt composition tends uniform, and the TiB2 phase eventually will be refined.