Search results

Particle properties analyses showed that LiMg0.06Mn1.94O4 sintered at 600 °C has a single phase and the average grain size is about 80-200 nm with a little agglomeration, it also displays the highest initial capacity of 114.2 mAh/g and still remains 82.7% after 40 cycles.
The grain sizes become bigger with increasing sintered temperature.
SEM of LiMg0.06Mn1.94O4 sintered at (a) 600°C, (b) 700 °C and (c) 800 °C for 3 hours Charge-discharge studies.Fig. 4 shows the discharge capacity vs. cycle numbers of LiMg0.06Mn1.94O4 sintered at different temperatures.
When the sintered temperature reach 800 °C, LiMg0.06Mn1.94O4 has poor electrical performance, because its worse crystallinity, bigger grain size and impurity .
The discharge capacity vs. cycle number of LiMg0.06Mn1.94O4 sintered at different temperatures Electrochemical Impedance Spectroscopy (EIS) Analysis.Fig.5. shows Nyquist plots of electrodes of LiMg0.06Mn1.94O4 samples obtained after 10 cycles at charged state and presented the equivalent circuit.

The parent material itself is rolled and the grains are extruded.
Fig. 2 (I) shows a small number of twins.
The largest number of twins is shown in Fig.4 (f).
The grains in Fig.5 are smaller than those in the base metal, especially in Fig.5 (a), where the grain size is the smallest and a large number of twins occur.
The grain will also coarser and the performance will decrease

Compared with macro components a mean grain size of for example 10 to 20 µm leads to a significantly decreased number of grains over the cross section that increases the impact of single grains on the material behaviour [1,2] and reduces the number of available gliding systems for cold forming.
Therefore, smaller grains with a homogeneous distribution of alloying elements have to be the aim of such a recrystallisation annealing treatment.
The bright field images (Fig. 3a&b) show very fine homogeneously distributed, but unexpected precipitates all over the grains.
Both samples, being aged at 10 and 50 hours, still show punctiform and evenly distributed precipitates all over the grains (Fig. 4).
Fig. 4c shows that they increase in size and number for very long ageing times of 50 h.

Phase composition (including crystallographic phases), preferred orientation of grains (crystallographic texture), grain size distribution, and quality of interfaces are recognized as parameters that affect the device performance and reliability.
As the dual damascene processing of copper matures and the number of physical defects is reduced and weak interfaces between copper and dielectric are eliminated [10-11], the microstructure of copper (texture, grain size, and grain boundary character distribution) play even more important role in reliability of interconnects [12].
Texture may be associated with a specific grain size and texture roughness.
In CVD W films the (411) texture is typical of smaller grains as opposed to larger, protruding grains with a (110) orientation [23].
Grain size is reflected by FWHM of copper diffraction peaks.

For this reason we concentrate in this contribution on grain-scale effects [1-4].
surface displacements due to their different orientation factors and resulting shape changes ε ρ mdbmd = ∝ v surface co-deformation of hard and soft phases hard and soft matter assembled in one microstructure ()miR σσ −∝ ridging and roping collective deformation of larger sets of grains typically resulting in a banded surface topology ()ba MMiP − ∝ b: Burgers vector; a: atomic spacing; S: elastic compliance; σ: stress; M: Taylor factor; ρ: density of mobile dislocations; v: velocity of dislocations; D: Diffusion coefficient (for bulk or grain boundary diffusion); kB: Boltzmann constant; T: absolute temperature; d: grain size with exponent -n, where n is 2 or 3 (bulk or grain boundary creep); vz: twinned volume of a grain; va: athermally transformed volume of a grain; m: Schmid factor; R, P: effective elastic-plastic compliances; σi: stress in the inclusion; σm: stress in the matrix; i: number of grains in a banded microtexture
cluster; Ma: Taylor factor of hard grains in a banded microtexture cluster; Mi: Taylor factor of soft grains in a banded microtexture cluster.
Sample A showed a homogeneous grain morphology with randomly distributed texture components.
In sample D banded long range roughness dominated over the grain-scale roughness pattern [5,6].

A large number of lattice defects such as surface humps, dislocations and stacking fault exist in the surface of the WC powder after chemical activation technique.
The effect of microscopic defects on grain growth in sintering has been analyzed by J.
As it can be seen from Fig.4 (a), the particles have a large number of horizontal and vertical stacking faults.
Richter, Grain growth inhibition of hardmetals during initial heat-up,Int.
Gestrich, A.Michaelis, Grain growth during sintering of tungsten carbide ceramics, Int.

However, at 1023 K, the fatigue strength at q = 90° in the low-cycle region is similar to that of the cast alloys with HIP, due to the fine grain size after EBM.
However, coarser grains, shrinkage defects, contamination from the crucible and oxidation during casting are significant concerns.
In Ti-rich TiAl alloys, the microstructure generally varies with the annealing condition as follows: (1) a fully lamellar structure composed of TiAl (g) and Ti3Al (a2) phases; (2) a duplex structure composed of fine lamellar grains and g grains; and (3) a near g structure mainly composed of equiaxed g grains.
The layered microstructure consists of a duplex-like region and equiaxed g grains forming a chain perpendicular to the building direction.
The stress amplitude-number of cycles to failure (S-Nf) curves of q = 0° and q = 90° cyclically deformed at RT are shown in Fig. 2.

Single-line Voigt function method [9] was applied for calculations of microstrains and average grain sizes using {111} diffraction line of γ and γ’ phases.
Grain size of γ/γ´ calculated according to fundamental parameters approach [10] was in the range from 20 to 30 nm.
Since the 2θ311(sin²ψ) plots repeatedly exhibited the so called ψ splitting, shear RS τT and τL are displayed as functions of number of the tool’s teeth in Fig. 5 a, b regardless of the tool feed value.
However, we did not observe any mutual relationship between machining parameters and either grain sizes or microstrains.
Moreover, the obtained values of shear stresses increased with increasing number of cutter’s teeth.

After annealing for 20 h at 900 0C large γ precipitates were dispersed, they decorated mainly the grain boundaries.
For the martensitic alloys the as-cast state specimens were characterized by great number of the micro and nanotwins (Fig. 4a,b).
The number of the γ' particles increases in the course of the treatment time.
Large γ precipitates were dispersed, they decorated the grain boundaries and created the colonies of the small precipitates inside the grains.

Throughout the review, it is proven that when 0.5% of Ga is added, the shear force is improved and the grain size of the solder has refined remarkably.
Several number of studies found have found the faceted Cu6Sn5 phase has grown quickly during annealing process or during service conditions.
In addition, the finest grain refinement and the most uniform structure was obtained at the addition of Ga at 0.5 wt.%.
Consequently, β-Sn dendrite has been suppressed and the grains size was decreased.
Nogita, Scientific Reports Vol 7, Article number: 40010, (2017) [2] S.A.