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This paper introduces the influence of the shape, grain size, density and hardness of abrasives particles on nozzle wear.
Under the same power, pressure and flow rate, the grain size has an optimal value, which gives the highest cutting efficiency.
When higher than it, the wear rate doesn’t change although the grain size increases.
The pre-mixed AWJ choose the grain size that is higher than critical dimension, so the grain size doesn’t have great influence.
Ca is Wear rate under high hardness abrasive wear, abrasive wear has no effect on material wear rate when the value of Ca is equal to 1, the result is shown in Fig.1.Based on large numbers of data, he verified that when K1 is in the range of 1.3 to 1.7, it has no influence on Ca, that is hard abrasive wear.

The reduction in resistance to electrical degradation upon the addition of Y2O3 to Bi-manganese (Mn)-Co-silicon (Si)-chromium (Cr)-nickel (Ni)-added ZnO varistors with the same composition as a commercial varistor except for Sb (the basic varistor) is due to an increase in the number of willemite (Zn2SiO4) particles or a reduction in the number of spinel (Zn2SnO4) particles at the grain boundary between two ZnO grains [8].
The average size of 200 ZnO grains was estimated from optical microscopy images (ECLIPSE Me600, NIKON) by taking the grain size to be equal to the side length of a square with the same area.
The average grain size of ZnO decreased with increasing amount of SnO2 and Y2O3.
(a) varistor voltage (b) average grain size Fig. 2.
It is speculated that the improvement in the resistance to electrical degradation is due the increasing number of spinel (Zn2SnO4) particles at the grain boundary between two ZnO grains [7].

This stage is characterized by slow sintering to form the initial grain particles.
With further sintering occurred, because of the mismatch of ionic radius, electro negativity and valence between Sn4+ and Pr3+, it would form a large number of lattice oxygen vacancies, free electrons and dislocations and other defects [9].
When the sinter continues, doping ions were rich in the grain boundaries, which can resulte in the emergence of the liquid phase, and boost the sinter; finally, an increase in the concentration of the dopants in the grain boundaries could induce the formation of the secondary phase.
Effects of Pr dopant on grain boundary and electrical properties of Ce5.2Sm0.8MoO15－δ, Acta Chimicasinica ,14 (2007) 1313-1317
Grain-boundary segregation and precipitates in La2O3 and Pr2O3 doped SnO2-CoO-based varistors.

The model was developed by summarising experimental data from a number of researchers, not from a systematic study on a single grade using a single experimental technique.
A previous investigation by the authors [7], using a homogenised steel slab with 0.045 wt% Nb, has shown that using the Dutta-Sellars equations with the mode grain size overestimates the degree of recrystallisation by up to 20 % for deformation to a 0.3 strain at temperatures above 1010 °C, whilst modelling the behaviour for individual grain size classes (i.e. considering the whole grain size distribution) gave better agreement for the degree of recrystallisation.
Quantification of recrystallised fraction at 0.3 strain In the previous study a simple approach was used to predict the grain size distribution after deformation by determining the recrystallised fraction for each individual grain size class [7] as grain size prediction equations in the literature were found to have the wrong form for the experimental distributions.
It can be seen from the figure that the recrystallised state can be predicted more accurately using the Dutta-Sellars equations based on individual grain size class compared to the mode grain size.
Due to the small size and numbers of these precipitates, they may have previously been considered absent and pinning ascribed to solute drag as previously reported for low pass strain (0.1-0.2) recrystallisation of austenite [10].

Introduction Silicon nitride based materials have found a large number of applications in different industrial fields over the past years due to their well-known good mechanical and thermal properties [1].
It is clear that grain growth occurs in the matrix, with the development of larger aspect ratio prismatic grains, characteristic of �-Si3N4 phase.
Also, finer particles are known to increase the densification due to a higher solubility, larger specific surface area or increased number of interparticle contacts by volume.
Although SiC replaces Si3N4 in the composites, it does not dissolve and reprecipitate from the liquid phase [7] and thus contributes only in a faint way for the grain growth or grain rearranging during sintering.
SiC inhibits grain growth of the Si3N4 grains and prevents weight loss even for long sintering times.

In a second experiment the dissolution of Cr into W grains at 1300oC was followed and found to take place preferentially along grain boundaries.
The grain size grow to the range of 40-80mm.
Each large grain contains many small second phase particles that were identified as Cr particles in W grains and W particles in Cr grains (Fig. 3).
Yet some W rich grains contain Cr rich precipitates and the Cr-rich phase grains are decorated with a gray layer that is a Cr-W solution.
After the sort anneal and fast cooling, the general grain structure remained unaltered but many fine lines, apparently delineating grain boundaries, were discerned in the Back Scattered Electron (BSE) image that is sensitive to the atomic number of the elements on the surface.

Fine Grain Distribution of Crushed Clay Brick Figure 2.
Coarse Grain Distribution of Crushed Clay Brick Table 1.
Concrete Int, Vol. 5, Number, 2, pp. 58–63 (1983) [2] A.
ACI Mater J, Vol. 91, Number 4, pp. 401-407 (1994) [3] A.
Mag Concrete Res, Vol. 53, Number 6, pp. 367-375 (2001) [4] T.

A large number of Al2Nd particles precipitation is the key factor to the highest hardness value(139.4Hv) in 2%Nd magnesium alloy after 370℃/3h+205℃/24h heat treatment.
Introduction spray deposited magnesium alloy has tiny grain, uniform in microstructure, it can improve mechanical property and corrosion resistance immensely[1-5].
These will pinning dislocations and block movement of grain boundary, increasing the hardness of Mg matrix.
With the solution temperature increased(420℃, 450℃, 480℃), coarsening both grains and a few of nano-scale second phase grains in heat treatment progress will reduce the hardness of Mg alloy.
The hardness of 2%Nd is the highest(139.4Hv) after heat treatment(370℃/3h+205℃/24h), the reason is large number of nano-scale Al2Nd precipited.

The average grain size is about 150nm and a striped multi-domain structure is exhibited in individual grains.
Up to now, a large number of investigations have been done on PFM imaging parameters, theoretically and experimentally [11] [12].
The vertical dashed line marks the boundary location between the two grains.
A striped multi-domain structure is also exhibited in individual grains.
Conclusion PTO polycrystalline grain films with tetragonal structure were successfully fabricated by sol-gel method.

Numbers, locations and thickness of the tubes were listed in table1.
Refer to OM observation, the representative microstructure were shown in Fig.1~4, the grain size and the spherical grade were listed in table 2
And in which the grain size ranged from 6 to 7 grade, structure was uniformly and abnormal crystal thicken not existed.
However, refer to the picture of the microstructure, no remarkable growth in grain and cavity not occurred along grain boundary, which revealed that creep damage in service at high temperature for a long time has not to severe extent.
Six specimens were ready for each number, so summed in 48 pieces.