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Introduction Cutting tools have been coated with a myriad of coatings for a variety of purposes for a number of years.
The coating researched in this work looks not at coating the individual grains, but coating the entire grinding wheel (grain and bond) with a coating to provide increased wheel life and improved grinding capability.
The claim was that the coating stabilized and reinforced the existing bond between the cBN grain and the wheel core.
Two identical grinding wheels were purchased, 300mm (12") diameter, 25mm (1") wide, plated with 60 grain GE 500 series cBN.
The grinding wheel was 300mm (12") in diameter, 25mm (1") wide and plated with 60/80 grain GE 500 series cBN.

Fig. 5 shows the relationship curve between the average grains size of Al-1.1Mg-0.6Si-0.4Cu alloy calipers and the forging pressure.
It can be seen that the microstructure of Al-1.1Mg-0.6Si-0.4Cu alloy calipers without forging was consisted of coarse dendrites, and the average grains size was about 55 μm, as shown in Fig. 4 (a) and Fig. 5.
When the forging pressure increased to 150 MPa, the microstructure of the Al-1.1Mg-0.6Si-0.4Cu alloy calipers were refined to fine and uniform equiaxed grains with a average grains size of 39 μm, and the shrinkage voids were removed completely, as shown in Fig. 4 (d) and Fig. 5.
Fig.5 Relationship between the average grains size of Al-1.1Mg-0.6Si-0.4Cu alloy automobile brake calipers and the forging pressure Mechanical properties of Al-1.1Mg-0.6Si-0.4Cu alloy calipers.
With the increase of forging pressure, the number and depth of the tough nests in the tensile fracture images of Al-1.1Mg-0.6Si-0.4Cu alloy calipers significantly increased, as shown in Fig. 7 (b), (c) and (d).

However, the poor formability of magnesium alloys, which is the result of their limited numbers in hexagonal close packed (hcp) crystal structure, restricts their widespread application as wrought magnesium alloy products [1-4].
As shown in the optical microstructures along three directions, hot-extruded AZ31 bar had a twin-free equiaxed grain structure with an average grain size of ~13.8 μm.
After annealing, the microstructure remained equiaxed, while the average grain size was slightly increased to be ~14.5μm.
,Grain refining of magnesium alloy AZ31 by rolling, 140 (2003) 588-591
China,Effects of grain size on shift of neutral layer of AZ31 magnesium alloy under warm condition, 25 (2015) 732-737

Similarly to the virtual MMCs previously analysed, MMC A, whose particles concentrate around the primary phase grains, which leads to frequent clustering, gives rise to a two-mode distribution.
The large primary phase grain size in MMC A is related to its slow cooling rate during composite solidification.
In such a case, dij distribution can provide an estimate of the average primary phase grain size, which may be useful to the calculation of the effective cooling rate.
a) b) Figure 3 - a) Distribution of Euclidian distances between particle centroids in MMC A, and corresponding average primary phase grain size estimate. b) Comparison of the estimate with a micrograph of the material.
indirect indication about primary phase grain size.

Due to the fatigue fracture of the welded joint often happens at the weld toe [8-10], the residual compressive stress and fine grain structure were obtain in the weld toe and its nearby area by ultrasonic impact treatment, the effect of residual stress on the fatigue life of 16MnR welded cruciform joint was researched under the condition of the same stress concentration coefficient and grain size.
The residual stress relief was carried out in SX2-4-10 type chamber electric furnace at the temperature of 200 (in order to prevent the grain growth) degree centigrade for at least 2 hours.
Fig. 4 is a bright field image of HRTEM of the treated specimen, it can be seen that the grain size in the surface of weld toe and its nearby area have be refined obviously.
The main reason for improving the fatigue life are refining the grain size in the surface of weld tie, making the surface always in a state of compressive stress, decreasing the stress concentration in the weld toe, which is caused by ultrasonic impact.
The main reason for improving the fatigue life are refining the grain size in the surface of weld tie, making the surface always in a state of compressive stress, decreasing the stress concentration in the weld toe, which is caused by ultrasonic impact.

The cost-effective manufacture of near-net shape titanium articles from sintered powders reduces the number of machining processes.
Therefore, grain growth was reduced.
The poor elongation is due to the coarse primary β-grain, as Fe is a strong β-stable element.
The microstracture of Ti-Mo alloy can be seen coarse-grained α-Ti phase Conclusions 1.
Al is a α-stable element, so the enhancement of the α-phase is acceleration and shown the grain growth. 3.

The progress of fatigue damage depends on the number of load cycles, intensity and kind of loading, as well as the state of applied steel [15-16].
Table 2 Chemical composition of compression plates Sample Chemical composition [wt. %] C Cr Ni Mo Mn Plate H 0,043 16,28 9,11 4.82 1,34 Plate F 0,043 16,66 10,58 3.88 1,65 ISO 5832-E ≤ 0,03 17-19 13–15 2.00–4.00 ≤ 2 Representative optical micrograph for tested steel is shown in Fig. 2.and Fig.3 It can be understood that their microstructure consist of a single phase matrix containing of average grains size of austenite.
A B Fig. 3 Microhardness of the plate H in (A) the center of the grain and (B) joint of the grain A B Fig. 4 Micro hardness of the plate at (A) the center of the grain and (B) joint of the grain Fig. 5 Microhardness of the compression plates in the center of the grain Fig. 6 Microhardness of the compression plates in the joint of the grain From these results, the microhardness of compression plates are homogeneous, the average microhardness of the compression plates are similar. 3.3.

Average grain size was 39 mm.
Fig. 1. shows AFM image of metallic surface of the grain of 316L steel cycled with constant plastic strain amplitude eap = 1×10–3 in the early stage, i.e. for N = 500 cycles.
Fig. 2 shows AFM image of plastic replica of the surface grain of 316L steel cycled with constant plastic strain amplitude eap = 1×10–3 later in fatigue life i.e. for N = 2000 cycles.
A small difference in the height of the surface of the grain left to the PSM A and the surface right is apparent.
AFM image of plastic replica of the surface grain of 316L steel cycled with eap = 1×10–3 for N = 5000.

Compared with the graphene added samples, the MgO ceramics have coarser grains and microstructures with nearly pore-free.
It may be caused by the wrapping effect of graphene and results in finer grain sizes [13].
As seen in Fig. 3(d-h), the MgO/Graphene samples show the grains coarsen with increasing sintering temperature.
It can be seen from Fig. 5(b) that the number of graphene layers is approximately 4-5.
The prepared MgO/Graphene composites showed grains coarsen with increasing sintering temperature.

Figure 3 highlights the prior austenite grain boundaries after austenitizing at different temperatures.
Grain coarsening was observed with increasing austenitization temperature, resulting in less grain boundaries, lower defect (such as dislocation, vacancy) density and higher homogeneity of alloying element (carbon, manganese, etc) distribution.
When considering heterogeneous nucleation in solid phase transformation, high temperature austenitizing heat treatment is not desirable for the subsequent austenite→bainite transformation during cooling as there is a reduction in the number of nucleation sites.
It is known that a larger driving force (free energy) ΔGV is required for bainitic transformation.[10] Figure 3 - Optical micrographs of the prior austenite grain boundary morphology for samples austenitized at different temperatures (a.880°C b.920°C c.960°C d.1000°C) Figure 4 shows the optical microstructure of isothermally transformed samples.
This outcome is due to the differences in prior austenite grain size, and the defect density in austenite which influences the nucleation and growth of bainitic ferrite.