Search results

Today the deep drawing process is already used to produce large numbers of small parts (diameter < 1 mm) at low costs per part.
An increasing number of grains at the surface, which are less restricted than volume grains, leads to less hardening in the surface layer and the directly adjoining grains [1, 3, 5-8]
With an increasing ratio up to ~ 0.2 (5 grains over foil thickness) the strength of a metal reduces for constant grain sizes and decreasing number of grains over the cross section if a critical material dependant value is reached (Table 2), as shown in [5-8].
In the work of [12] a number of 50 grains over the cross-section is given as a critical value influencing the flow stress of a metal.
Critical grain number depending on material Source Material Grain size [µm] Critical grain number Cu 65 5 - 7 [5-7] Cu-13 at% Al 40 10 - 15 [8] Sn and Sn alloys ~ 20 Influence of Punch Velocity on the Punch Force.

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.

In the current model, the dynamically recrystallized microstructure will be represented by certain number of representative grain aggregate with different component and different cycle of DRX.
Each grain aggregate has state variables of the component number, dislocation densities, surface boundary area, sum of grain diameter in the grain aggregate, number of grains in the aggregate and volume fraction of grain aggregate.
Where, i represent DRX cycle and j represent component number.
Then, number of nuclei for grain aggregate [j,i] can be defined as follows. . (5) where n, m, Qnucl are constants, f is the volume fraction and Δt is a time increment.
The final tube has an outer diameter of 48.8 mm with thickness of 4mm.The total number of triangular elements used was 4471.

A small amount of CoO up to ~ 0.3 mol% was effective for the suppression of grain growth, but the addition of 1.0 mole % resulted in an enhanced grain growth.
A small amount of dopant suppressed the grain growth.
In fact, extra ordinary large grain was not observed.
A small amount of CoO up to ~ 0.3 mol % was effective for the suppression of grain growth, but the addition of 1.0 mol % resulted in an enhanced grain growth.
A small amount of CoO up to ~ 0.3 mol % was effective for the suppression of grain growth, but the addition of 1.0 mol % resulted in an enhanced grain growth.

Methodology Simulation of grain shape.
The idealized shapes of grains are symmetrical, which can be simulated by combining a fixed number of overlapping disc elements connecting in a rigid way.
Fig.1 Generation algorithm of two kinds of grain shapes and difiniton of grain orientation.
Contact law between grains.
Grain orientation mainly effects the movement including motion and rotation of grains in mesoscopic level.

But there are only a small number of reports on the microstructure of EEUSS coatings yet, and very few studies concerning the grain abrasion properties of the EEUSS coatings have been done.
Also, the liquid metals surrounding TiC grains give rise to the increased diffusion path, reduce the driving force for TiC grain growth, and prevent the sintering between TiC grains to form larger grains.
The compact fine grain microstructure also increases the abrasion resistance.
The effect of nickel additive decreases the size of TiC grains to submicron.
The coating with 15 wt. % Ni additions has an excellent grain abrasive resistance.

It focuses on the measurement of sulphur grain boundary segregation in nickel on fractured surfaces.
Analysis of sulphur grain boundary segregation on a nickel fracture surface by EPMA-WDS.
Sulphur grain boundary segregation kinetics at 750°C Figure 6.
Sulphur grain boundary segregation at 750°C measured by EPMA-WDS.
McLean: Grain Boundaries in Metals.

Alloy added into the aluminum melt after stir the melting and mixing, heat preservation 10min after pouring into the four cast, which was followed by the number 4 group No.1 ~ No.4 (n = 4, the steel mould, graphite mould ,copper mould and Water-cooled copper mould number were a, b, c, d) test like.
Among them, die casting of No.2 (a) and No.3 (a) sample grain size is larger, the water-cooled copper mold casting of No.2 (d) and No.3 (d) sample grain size.
From the experimental results, has an important effect to the formation and size of aluminum melt pouring temperature on Al-5Ti-B alloy microstructure refinement of pure aluminum ingot of equiaxed grain, especially as the mass fraction of Al-5Ti-B alloy is 0.2% and below, the pouring temperature of melt increases, ingot organization columnar grain number, grain size.
In the Al-5Ti-B alloy additions are the same, because the cooling speed melt faster, a lot of equiaxed primary crystal formation type wall can be preserved in the melt more equiaxed dendrite microstructure, the number of the more, the more fine grain.
Conclusion The TiAl3 and TiB2 contained in Al-5Ti-B alloy have good grain refinement ability for commercially pure aluminum, and the cooling rate and casting temperature have significant effects on the number and size of equiaxial crystal.

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.

Table 3: Number of grains observed and traces with their inclination relative to RD.
Indeed, a large number of well defined bands are seen inside γ grains.
The Taylor factor does not take into account the number of slip systems which are actually activated to accommodate the local deformation.
If the local misorientation is correlated with the degree of fragmentation (as it seems to be from the EBSD images where crossed slip traces are more numerous in highly misoriented grains), then it should be correlated with the number of slip systems activated in each grain.
The number of bands which can correspond to a <110> pole increases with strain, so does the number of γ grains.