Search results

Abrasive grains used for lapping have sharp, irregular shapes.
The polymer used is confidential and no details can be given except that it is the object of the US patent number.
It is found from equation (3) that the surface roughness increases with the increase of pressure and decreases with the increase of lapping time, speed and grit number.
Similarly, from equation (7) it is observed that MRR increases when lapping speed and pressure increase and grit number decreases.
But the smoothness that can be achieved by lapping is not unlimited, even when very fine abrasive grains are used [2].

Grain size were detected according to [19].
A significant number of fragments along the specimen’s edge were formed by plastic shear and tearing.
A large number of sizeable inclusions were detected at the bottom of some depressions (Fig. 4, c). 3.4.
Methods for detection and determination of grain size
Micrographic determination of the apparent grain size (ISO 643:2003, IDT)

Introduction Manufacturing process of heavy forging includes a high number of specifics starting with production of ingots and their primary heat treatment followed by free forging operations and final heat treatment.
This laboratory processing was performed with aim to reach coarse grain and increased precipitation potential.
It is evident that absorbed energy is significantly higher in case of Ni-Cr steel in all evaluated states (100 °C – 600 °C) despite the coarse-grained matrix.
Prior austenite grain is coarse.
Hall, Carbide precipitation, grain boundary segregation, and temper embrittlement in NiCrMoV rotor steels, Metallurgical Trans.

The grain morphology, with a high aspect ratio, is connected to the strong anisotropy of the crystal structure and gives rise to extreme anisotropy of polarization [2].
Typical plate-like morphology with the average grain size of ~5 µm is observed in the pure and La modified bismuth titanate ceramics (Fig. 2).
In comparison to the pure and La substituted bismuth titanate the BT ceramic with cerium has a large number of the grains fractured in trans-granular manner.
The observed decrease in the fracture toughness with addition of La and especially Ce (Fig. 4) could be also connected to the grain morphology.
Typical plate-like morphology with the average grain size of ~5 µm is observed in the pure and La modified bismuth titanate ceramics.

The microstructure indicates white β-phase dispersed on the grain boundaries of dark α-phase.
A number of surface modification techniques, such as physical vapour deposition (PVD), plasma immersion ion implantation, thermal oxidation, plasma and laser nitriding, have been recently applied to titanium alloys, mainly to the more widely-used Ti-6Al-4V, to improve their tribological behaviour.
Various literatures [16, 17] have shown that the β-phase precipitates on the grain boundaries of α-phase with refinement of β-phase on cryo-treatment.
For the as-received sample, the microstructure showed 235132 black pixels and 27012 white pixels; the corresponding numbers for the cryogenically treated sample were 237858 black pixels and 24286 white pixels.
It was observed that grain coarsening of α phase has taken place after cryo- treatment.

The calcium dissolved into the matrix or compound phase and have an uneven distribution, but it can improve the distribution of β-Mg17Al12 phase ,refine the grain and improve the mechanical properties.
With the number of Ca increasing, Al2Ca phase could be formed with high melting point, while β-Mg17Al12 phase would be decreased, which greatly improve the high-temperature performance.
There are also some particles appearing in the grain boundary.
When adding 0.3％Ca, the microstructure of α-Mg matrix could be refined, the grain could be uniformed and the β phase appears tiny.
When adding 0.6％ Ca, particles in the grain boundary have a notable increase.

Both the upper bound Taylor and the lower bound Sachs models ignore the interactions among the grains.
The interaction between the grain and the HEM is carried out by a visco-plastic Eshelby approach.
The model iterates to a solution where the HEM represents the average response of the grain population used.
Metals with hcp crystalline structures have reduced number of available slip systems compared to cubic structures, making plastic deformation more difficult.
To start with we generate 1000 grains with random orientations.

By Gauss curve fitting and area calculation, crystallinity fraction XC and grain sizes d of these films can be calculated from Eq. 1 and Eq. 2.
Table 1 shows the crystallinity fraction XC and grain sizes d of these films.
It is to be noted from Fig. 3 that the grain sizes of thin films are increasing as the annealing temperature rises, at the same time there are a lot of conglobation structures formed by merger of grain clusters with annealing temperature increasing.
Fig. 3: AFM topographies of thin films annealed at different temperature: 250℃(a), 300℃(b), 350 ℃(c), and 400℃(d) The reasons for the decline of the resistivity of the annealed samples may be due to acceptor behavior of the B atoms activated by H atoms migration, which can destroy numbers of B-H-Si bonds and result in hole carrier increasing as the acceptor impurity.
So if the effect of grain sizes is more prominent than that of crystallinity fraction, the effect of grain sizes will be dominant in effect on resistivity.

The great mass of grains are anomalistic strip, which is also in favor of the improvement of mechanical properties because strip-type grains are easier to pile together crosswise, and imprison the spread of cracks in a way [8].
The grain and pore size of the porous mullite coating are only about 15~20µm and 3~5µm, respectively (Fig.3 (b)).
Grains heaped up promiscuously with a bit of sheet-type grains.
Pores were formed in the process of removing organic additives and growth of grains.
Mullite grains formed a great number of second-clusters in each macropore of the porous silicon carbide support, which guaranteed that clusters aggregated shoulder by shoulder and prevented mullite grains from entering into the bowel space of porous silicon carbide support. 47 48 49 50 51 52 53 54 0.000 0.005 0.010 0.015 0.020 0.025 dV/dlogD Pore Volume (ml/g) (a) Porous SiC support Pore size distribution (µm) 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 0.000 0.002 0.004 0.006 0.008 0.010 0.012 Pore size distribution (µm) (b) Porous mullite coating dV/dlogD Pore Volume (ml/g) Fig. 4 Pore size distribution of samples.

It was shown that the CMC content had a direct influence on the grain size and crystallinity degree(χc ) of HAp: The higher the CMC/HAp ratio, the lower the HAp grain size and the crystallinity degree.
However, the ageing time has no obvious influence on the grain size and χc of HAp, Table 1.
This development of HAp grains will then grow along the chain direction of CMC.
In this way, the alignment of HAp grains was resulted.
Vol.267 (1992), p5968 Ca(NO3)2⋅H2O HAp grains Ca 2+ (NH4)2HPO4 [5] R.H.