Search results

From the damage aspect it is not possible to deduce the maximum main stress direction Re-inspect after max. 30000 hours 3 Orientated Cavities were observed, often multiple cavities on the same grain boundary.
A clear orientation of the grain boundary damage can be observed, indicating the maximum main stresses direction Re-inspect after max. 15000 hours 4 Microcracks The cavities are observed on the limits, perpendicular to the maximum main stress direction.
Limited service until repair Repair / replace in maximum 10000 hours 5 Macrocracks In addition to highlighted cavities and micro-cracks, the micro-cracks join and form macro-cracks extend along the length of several grain boundaries.
Remaining life assessment The quantitative evaluation of the replicas is made on the basis of parameter A, calculated (2) according to the SPRINT SPI 249 procedure: A= (2) where: Nu- Number of undamaged grain limits; Nd - Number of damaged grain limits.
Conclusions In this case, by the non-destructive method of metallographic replicas, a smaller number of operating hours was estimated (of 10905 hours) than by destructive creep test method (of 13997 hours).

There are a large number of dimples at the fracture.
A large number of studies have found that the saturation magnetization of an alloy depends not only on the number of ferromagnetic domains, but also on the geometric configuration of the domains, such as size, morphology, and arrangement state [14].
The coercive force has a strong dependence on the grain size of the alloy [15-17].
It is generally believed that as the grain size increases, the coercive force decreases.
Doole, Thickness and grain-size dependence of the coercivity in permalloy thin films, J.

Fig.2 (c) displayed the disorientation angle distribution of the α grains.
Comparing with the cold-rolled sample (Fig. 2 (b)), one can find that numerous fine β precipitates formed at the α grain boundaries and in the α grain interiors.
The results were obtained from the examination on a large number of randomly selected β precipitates in the ECPed sample.
Fig. 3 TEM bright field image showing dislocations in the interior of α grains.
Gou, Grain refinement and formation of ultrafine-grained microstructure in a low-carbon steel under electropulsing, J.

As it is shown, the grains are uniform and nearly equiaxial and there is no columnar grain structure in the DP alloy.
The average grain size is ~16 nm, based on a measurement of about 500 grains.
The selected area electron diffraction pattern in the inset of Fig. 7(c) reveals again a fine grain size and random grain orientation.
The statistical grain size distribution taken from the TEM images shows an average grain size of 25 nm.
The reduced number or density of propagating dislocations due to this enhanced dislocation absorption process is a possible mechanism for the increased v* with strain rate at high strain rates [Fig. 9(b)].

In addition, from origin to remarkable structure and patterns of sand dunes is very complex, however any number of objects, such as shrubs, rocks or fence posts can obstruct the wind force causing sand to pile up in drifts and ultimately large dunes as shown Fig.2.
t i Q uutgtuu d C dm Q dm l zyxL c a i s i s i a i s D s a ssss si ∆ ∂ ∂ −−       ∆−∆− ++= ))sin(1)(( 2 1 )( 8 3 ),,( 0 ρ ρ λ (1) Where ),,( zyxQn and ),,(1 zyxQn+ are height of sand grain ground surface before and after rising up point (x,y,z) on the local region respectively, the ),,( zyxLsi is sand grain's suspension distance, the 0l is base value of jumping distance, the cu is a sand grains critical wind velocity for jumping, aiu is wind velocity, aρ and sρ are the air and sand density respectively, sm and sd are express sand average mass and diameter respectively, λ is a sand grains shape coefficient, DC is a resistance coefficient, t∆ is a time step, siu is a sand grains speed, sig is a gravity acceleration.
The sand grains transferred volume, sand face coarseness and obstruct are primary reason of sand dune form.
The sand grains transferred volume expressed as, ))),,(sin(1(),,( zyxgmzyxq S +⋅=δ (2) Where, the affecting factor is ))),,(sin(1( zyxg+ , if sand grains in aweather inclined plane, it urge to banish more sand grains, if in lee-face it was been exactly the opposite results. δis a coefficient( In the dune form region 0<δ<1, in the non-dune form region δ=1).
(a) Wane Dune (b) Identical Child Dunes Formed and Moved along the Wind Direction Fig. 9 Real Child Dune and It's Moving Patten in Taklimakan Disert Conclusion The sand dune formation and shape will at least receives three factories influence, namely wind stream, sand grains transferring and various obstruct.

Number modeling of deformation behavior for Al-based powders coated on magnesium alloy by supersonic particles deposition WANG Xiaoming1, a, ZHU Sheng1, b, CHANG Qing1, c, FENG Xueqiang2,d and LIU Yuxiang1,e 1National key Laboratory for Remanufacturing, Academy of Armored Forces Engineering, Beijing 100072, China 2Department of Training, Academy of Armored Forces Engineering, Beijing 100072, China aemail,uwangxm@126.com,bemail,zusg@sina.com, cemail,chang2008qing@163.com, dfxkxlove@sina.com, e13811747945@163.com Keywords: Magnesium alloy, Supersonic Particles Deposition, Deformation Behavior, Number Modeling Abstract.
Results and Discussion Number Simulation of Particle Impinging Behavior.
Some particles had occurred severe plastic deformation under high speed collision, presented plastic stacking shape, generated metal jet at contacting interface; Some particles emerged obvious cracks owing to impact from the following spraying particles; Only a few of particles could keep the initial shape; Meanwhile, a large majority of fine grains adhered to the deformed whole particles.

The intensity due to grains which twin is essentially 'exchanged' between these two positions.
This also gives the opportunity to track the progress of 'parent' grains (grains which are aligned to twin) and 'daughter' grains (grains which have been reorientated by twinning) by basal plane, {0002}, or prism plane, { 10 1 0}, diffraction peaks [2].
In contrast, compression in TD results in a marked change in c-axis orientation, with most grains re- orienting such that their c-axis is parallel to the load axis.
In tension along TD, as in ND compression, we expect fewer grains to be oriented for tensile twinning.
Synchrotron experiments at HASYLab were funded by the German Ministry of Education and Research (BMBF) under contract number 05KS1MCA/2 (synchrotron diffraction).

As measured from the EBSD, average grain size in the fine-grain region is 9.5μm.
The smaller grain size increases the density of grain boundaries, which act as barriers to dislocation motion.
Therefore, the stress is larger in the fine grains in adjacent to coarse ones, while it is smaller inside the coarse grain.
Moreover, the atomic bonding in intermetallic compounds generally exists in multiple forms, such as ionic, covalent, metallic, and even molecular (van der Waals forces), so the number of free electrons is much less than that in the Mg phase bonded by metallic bonds.
"Heterogeneous lamella structure unites ultrafine-grain strength with coarse-grain ductility."

The photocatalytic activity of nano-ZnO is related to its crystallinity and grain size.
Then put the leach solution into a 500 ml beaker, and then put a certain number of galvanizing dross into the beaker.
In contrast, when calcination temperature is 400℃, the nano-ZnO crystallization has been completed, and because the nano-ZnO has smaller and uniform grain size, larger specific surface area and larger number of intergranular pore, nano-ZnO has the best photocatalytic activity at 400℃.
Porous nano-ZnO with different crystallinity and grain size were successfully obtained by controlling calcination temperature and time.
The crystallinity and grain size of nano-ZnO directly influence its photocatalytic activity.

In order to improve ductility of metallic glasses, a number of studies have been carried out.
The grain size of the crystalline precipitates is in a range from several nanometers to about 200 nm.
The crystalline nanoparticles with an average grain size of about 8 nm are observed.
(a) BF TEM image; (b) SAD pattern; and (c) NBD pattern taken from the grain indicated by arrow in (a).
The results indicated that the nanocrystalline structure composed of a monoclinic CuZr phase with an average grain size of about 8 nm and a glassy matrix is formed by electron irradiation induced crystallization, while by thermal annealing the equilibrium Cu10Zr7 and CuZr2 crystalline phases with the grain size ranged from several nanometers to about 200 nm precipitate from the glassy phase of the Cu50Zr45Ti5 glassy alloy.