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Distribution of BaSO4 particles in the initial state (1) and after 2-hour long heating at 800°C (2) The initial BaSO4 powder consists of grains 0.2 to 5 μm in size with a distribution peak at 0.95 μm.
Heating the powder at 800°C results in a decreasing concentration of grains due to their sintering.
Such structure and a large surface area provide (at the appropriate heating temperature) the fullest deposition of SiO2 nanoparticles onto the surface of micropowders’ grains and pellets.
The new grain sizes may be more optimal in relation to the wavelengths for obtaining maximum scattering.
In ρλ spectra of the initial and nanodispersed pre-irradiated BaSO4 powders, there is a number of dip-like absorption bands in the 200-400 nm.

In the aircraft industry, there are a considerable number of structural reinforcements that are realized by T-joints.
After the first examinations had been made, macro and microstructural characterizations were performed to assess the morphology of the joint and analyze the grain size.
Zirconium presence allows it to control the grain structure and also plays a beneficial nucleating effect on the δ' particles [10].
The latter has larger grains with marked orientation.
Finally, the HAZ shows larger grains than all the other parts and even presents lower hardness.

The αm was formed in the vicinity of prior β grain boundary (Fig. 3a-c) while the rest of the grain was occupied by α′ martensite.
It can be noted that there is a preference of the αm to form in the vicinity of the prior β grain boundary while the martensite was shown to be able to form in any part of the grain.
Thus, the αm is easily formed in the vicinity of the prior β grain boundary.
A higher cooling rate produced αm with a finer α width, containing a higher number of white particles. 4.
Zhan, Characterization and decompositional crystallography of the massive phase grains in an additively-manufactured Ti-6Al-4V alloy, Mater.

During laser heating of steel, the final grain size significantly depends on the heating rate, as well as on the equilibrium and ordering of the initial structure [7].
In hardened martensite, about 80% of the hydrogen is located at the boundaries of the former austenitic grains [12].
Hydrogen diffuses in the steel both along the grain boundaries and through the grain body.
At low temperatures, the grain boundary flow is predominant in metals, and with increasing temperature, the contribution of bulk diffusion increases rapidly.
Effect of hydrogen content and residual austenite on crack formation during laser quenching (40 tracks with a total length of 6000 mm were studied, samples were heated to 90±5°C) Steel Type of treatment Austenite content, % Hydrogen content, % х10-4 Number of cracks, pc.

Thus, in the presence of interstitial H atoms, vacancies are formed as vacancy-H clusters (VacHr’s) by trapping a multiple number (r) of H atoms.
A number of theoretical calculations have been made on various properties of SAVs; the configuration and energetics of Vac-H clusters in Be [18,19], Mg [20], Al [20-22], Fe [23], Ni [24,25] and Pd [26], vacancy-ordered structures [25,27], and the formation mechanisms of defect clusters [28-31].
The high-temperature peak (~ 600K) is due to detrapping from grain boundaries, the amount of which increases with increasing C contents as the grain size decreases.
Stress-corrosion cracking (SCC) of steels: Propagation of cracks in steels often proceeds intermittently, by successive interconnection of fissures formed at grain boundaries in front of crack tips.
They also showed that these voids tend to accumulate at grain boundaries to become embryos of fissures.

Two different types of sample preparation have so far been investigated, a single crystal heated under compression and a polycrystal annealed to produce a gradient of precipitate sizes between the grain interiors (GI) and the grain boundaries (GB) (largest precipitates in the GI, smaller ones at the GB).
The difference is a result of a substantially higher number density close to the GB compensating for a smaller volume of each individual precipitate in this region.
However, the higher volume fraction of Ni-rich precipitates close to the GB indicates a slightly higher Ni content in this area possibly due to grain boundary mediated diffusion processes (assuming a fixed 4:3 concentration ratio for the precipitates irrespective of their size).
The relatively homogeneous configuration in the interior of the grain can further be described by plotting the ratio’s i/l and s/i of the principal axes as seen in Fig. 5.
Support was also provided by the FWO project G.0576.09 “3D characterization of precipitates in Ni–Ti SMA by slice-and-view in a FIB-SEM dual-beam microscope” and a BELSPO project entitled “Physics based multilevel mechanics of metals” under the IAP framework, contract number P6-24.

Thus, positrons are attracted more to O ions than to Mg ones (still other factors like the size and proton number of atoms involved may play a role).
The iron oxidation numbers Fe2+ or Fe3+ associated with lithiation and delithiation, respectively, can be monitored in detail with x-ray spectroscopy methods as described e.g. in [13].
In reality, cathodes are made of powder formed by grains with the size of about 100 nm size and the delithiated phase FePO4 exists only in the core of the grains within the nano-powder [14].
There are certainly interfaces among the grains, which may affect positron behavior.
Furthermore, all grains are not charged or discharged simultaneously, but rather one by one.

If sintering temperature is too high, which will lead the crystal grain to grow up and the crack is easy to produce.
Table 1 The effect of carbon fiber dispersion on bending properties Specimen number Sintering temperature/℃ Density /g·cm-3 Average /g·cm-3 Bending strength/MPa Average /MPa 1-3 1800 1.54,1.55,1.59 1.56 16.12,16.51,16.63 16.42 4-6 1850 1.60,1.61,1.62 1.61 17.98,18.77,19.68 18.81 7-9 1900 1.62,1.65,1.65 1.64 17.28,17.81,18.52 17.87 (a) (b) (c) (a) 1800℃ (b) 1850℃ (c)1900℃ Fig.3 The photograph of bending fracture From Tab.1 it can be seen that with increasing the sintering temperatue, the density of the brake composite is increased, and the bending strength of composite is raised first, and then decreased.
When the sintering temperature is 1900℃, the fiber structure is destroyed because the interface liquid phase penetrate into the fober aggravatingly, which decreased the fiber reinforcement, increased the grain number and led to reduce the property of the composite.

Controlled rolling in this paper can make the microstructure recrystallize repeatedly, inhibit grain growth, refine austenite grain, and finally achieve high performance requirement[6].
Table 2 Tensile properties of as rolled samples Number Yield strength [MPa] Ultimate tensile strength [MPa] Yield ratio Total elongation [%] Uniform elongation [%] Hardness [HV] AKV at -40°C [J] 21# 818 1083 0.76 16.6 3.8 324.8 247.1 22# 817 1078 0.76 16.6 4.1 336.6 234.3 Two pieces of steel have similar mechanical properties as shown in Table 2.
Table 4 Performance after quenching and tempering Number Yield strength [MPa] Ultimate tensile strength [MPa] Yield ratio Total elongation [%] Uniform elongation [%] Hardness [HV] AKV at -40°C [J] 21Q-0 868 1092 0.80 14.0 3.0 339.3 248.7 21Q-1 564 777 0.72 21.6 9.5 244.0 266.7 Compared21Q-0 with 21#, the strength of 21Q-0 sample increased slightly.

Fig. 1: Typical complex axisymmetrical part, numbers indicate some of the investigated zones.
We observe also that these effects are along the grain boundary where normally more liquid is present.
We start in zone 1 with a martensitic structure, than more and more perlite in the grain boundaries (troostite) surrounding the martensite (white area).
Part number 1 2 3 4 Cooling type air air oven oven Structure P+M P+M P P 1 421 477 359 374 2 427 450 350 363 3 422 448 345 361 4 413 416 351 365 5 420 413 348 366 6 407 391 338 359 7 436 439 357 365 8 443 444 369 380 Average 424 435 352 367 Standard deviation 12 27 9 7 This improvement is shown by the hardness distribution in the part (Table 1).