Search results

Although a number of studies have demonstrated the presence of sulfur at Al2O3/ bond coat layer interfaces [1,2], the detailed mechanism of the origin of the loss of adhesion remains under discussion.
In the case of TBC, the scale was identified as a duplex one, composed of an outer equiaxed grain layer and an inner columnar grain layer [10].
The results demonstrated the contribution of grain boundaries of the bond-coat external part in the sulfur diffusion (Fig. 8) [15].
Fig. 8. localization of S along grain boundaries of the bond-coat for a low sulfur sample after an hour of isothermal oxidation at 1100°C.
• Sulfur diffusion through the bond-coat is ensured by the grain boundaries of NiAlPt, which can explain the difference of behavior encountered between the bare superalloy and the bond-coated one.

Experimental Method Intersticial free used in this work has the following chemical composition, all numbers given in wt%, except where stated otherwise: 24ppmC, 9ppmN and 1.70Mn, 0.17Si, 0.006P, 0.002S, 0.021Al, 0.014Ti and 0.11Nb.
These critical strains are also weakly dependent on grain size and, in this regard, the grain size for the present experiments was kept constant.
In order to be thorough, it must be emphasized here that stresses are also dependent on initial grain size, through Eq. (4).
Increases in grain sizes also leads to increases in εp thus delaying DRX initiation.
However, experiments conducted in this work utilized samples with constant initial grain sizes and, therefore, the influence of this variable on stresses was neglected.

On the other hand, the grains changed from fibrous to coarse recrystallized (Fig. 2a,b for Al-Mg-Si alloys, grains in Al-Cu alloys were similar).
Both fibrous grains and particle distribution did not change.
Light microscopy micrographs: (a) recrystallized grains in AA6262-T6, (b) recrystallized grains in AA6023-T6, (c) fibrous structure and particles (d) in AA6262-T8+400°C/2h + slow cooling (sample B).
Spillard, A Lead-Free Aluminum Alloy Featuring “A” Rated Machinability, SAE Technical Papers, 1998, Paper Number: 980459, 61-68, http://papers.sae.org/980459

It reveals that the as-extruded alloy consists of fine and equiaxed grains with mean grain size of ~ 20 µm.
In this study, the alloy was not subjected to solution treatment before aging because we found that solution treatment usually induced serious grain coarsening for this type of alloy.
The arrows correspond to grain boundaries.
Second, the abundant phase boundaries between precipitates and matrix may act as dislocation sinks just like conventional grain boundaries, which can facilitate dynamic recovery and reduce strain hardening ability [17].
Compared to the as-extruded alloy, the solute content was largely reduced in the alloys aged at 150 ℃ and 210 ℃, and a large number of fine precipitates were formed in matrix.

Scholars [7] have already presented a ternary Ag-alloy bonding wire containing a large number of annealing twins.
The grain size of this annealing-twinned Ag-alloy wire remains almost unchanged during aging at 600 °C.
Moreover, the excellent thermal stability of the grain structure causes a shorter heat-affected zone near the free air ball of this twinned wire, and this type of wire also increases the light output (LOP) in 0605 (0.6 x 0.5 μinch) LED packages by around 3.2%.
The diffusion would be restricted due to the low energy of the twin boundaries; therefore, the grain growth driven by the electricity, light, heat and moisture effects in the continuous process of electricity could be obstructed.
Tu, Observation of atomic diffusion at twin-modified grain boundaries in copper, J.

According to TEM micrograph faceted surfaces was confirmed as high stability nanocrystalline grains (4A2).
The TEM micrograph allow us to compute the statistical grain sizes and it reveals the presence of non-agglomerated tin oxide nanoparticle with uniform particle size, which is ranging from 30 to 50 nm.
The decrease of resistance was observed as increasing the RH due to the injection large number of electrons.
Lin, Grain growth in nanocrystalline SnO2 prepared by sol-gel route, Nanostrut.
Kulkarni, Grain size effects on H2 gas sensitivity of thick film resistor using SnO2 nanoparticles, Thin Solid Films 295 (1997) 271-276

Introduction Aluminum production has been extensively used for many applications accordingly recycling of aluminum prompts a tremendous number of cost and environmental benefits.
Furthermore, the grain sizes of structure grain of extruded specimen according to optimum condition was tested; it was bigger than the grain size in received material.
Basically, if the grain size was bigger, the ultimate tensile strength was smaller.
These results were attributed to the smaller size of grain size and the created compounds (Cr23Ni5Si2 , Al86Fe24) during heat treatment process as shown in fig. 10 which describes X-ray diffraction (XRD) result of extruded specimen followed with heat treatment, it showed that the improvement of tensile strength was attributed to the amount of the created compounds by the heat-treatment process.

As is known, the flux can promote the crystallization process of phosphor within a certain range, but the grain coarsening and agglomerate of powders may generate with excess flux materials.17 In this paper, we used BaF2, H3BO3, Na2CO3 and NH4Cl to understand the effects of flux on the crystal structure, morphology and photoluminescence properties of CaAl12O19:Mn4+ phosphors.
SEM image shows big particles along with a large number of small particles and has a grain size of 1-8 μm.
The surface morphologies indicate a better grain growth, bigger particle size, improved crystallization after introducing the fluxes.
B2O3 enhances the solid-state reactions of CaO and Al2O3 powders by existing between them as a liquid phase that promotes the diffusion rate, leading to the grain densification and coarsening.
Better grain growth, bigger particle size, improves crystallization was obtained after introducing the fluxes.

The number of total knee arthoplasties will increase to 3.48 million procedures per year [1].
In annealed state the sample with 14 % Nb showed an acicular α` martensitic structure, whereas in the sample with 34 % Nb only the grain boundaries of equiaxed β grains were visible.
The grain boundaries are marked with a dotted line.
The grain boundaries are marked with a dotted line.
The annealed alloys showed an acicular martensitic structures when the Nb content was below 24 %, whereas at higher alloying contents equiaxed β grains were visible.

As Figure 2 showed, the surface morphology of K-feldspar grains have been significantly improved with increased grinding time.
In the early stage of grinding (0-15 minutes), K-feldspar grains were large, with few of fracture surface and defects, and the texture was strong.
After grinding for 15 minutes, large particles of K-feldspar grains reduced gradually, and the fine particles increased significantly.
There were obvious tearing signs in the surface of particle, and the number of fracture and defects increased.
Grinding beyond 45 minutes, in addition to reduction of particle size, the agglomeration of K-feldspar grains was evident and intensified with the extension of the grinding time.