Search results

These designs are designated 2k-p where k is the number of factors which may be evaluated in a full factorial design of size 2k, and p is the number of extra factors to be included [6].
Most of the grains appear to be clean.
Also, it is apparent that with increasing magnification, the precipitate particles are revealed within the grain and at the grain boundaries.
Most of the grains appear to be clean.
It is possible that these grains were saved by heavy precipitation along the grain boundaries, which prevented their movement.

It can be seen from table 1, with the increase in N flow of samples, 2θ angle of peak position in XRD diffraction curves increased, the grain size became bigger and crystal quality was better.
Fig.2[15] The forms of the N-N and N-O bond in ZnO Films Table 1 XRD peak data and the corresponding grain size of different samples Sample number b c d e f 2 Theda[°] 34.48 33.938 34.14 34.22 34.26 32.097 36.661 FWHM β[°] 0.869 1.022 0.589 0.479 0.455 0.795 0.937 Grain size[nm] 11.09 9.37 16.3 20.05 21.16 11.81 10.57 the grain size of the sample calculated using the Scherrer formula: （1） Where λ is the X-ray wavelength (about 1.5406nm), θ is the Bragg diffraction angle, β is the diffraction peak width at half maximum.
The band gap red shift of samples c, d and e could be explained from the quantum confinement theory [17], the following showed the relationship between value of the band gap and grain size: （2） Where Eg0 is energy gap for the lower body ZnO materials at room temperature, R is the grain size, ε is the dielectric constant and Er is the Rydberg energy (2.180 × 10-18J), The second term in formula (2) represents the blue shift caused by electronic hole confinement effect ,and the third item represents the red shift caused by the electron and hole Coulomb interaction.
In addition, there was also an absorption peak redshift 780cm-1 relative to 650cm-1 of intrinsic silicon oxide, this was because there were a large number of dislocations and stacking faults [18-20] between the substrate and the film,which resulted the tetrahedral structure of silicon-oxygen damaged and loose crystal structure.
Conclusion 1) a significant impact of N-flow on the film microstructure The film was amorphous and poor quality crystal when argon nitrogen flow ratio was 9/1,because N incorporation destructed the crystal structere and inhibited the binding of Zn-O bond and there were a large number of oxygen vacancies in the film.

In addition, due to ECAP refinement of grains can also be achieved [4-5].
Al cap was densified through ECAP via A-route (RA) and two number of passes.
Generally, Sintering leads to grain growth which results in reduction in hardness for UFG materials.
Langdon, The principles of grain refinement in equal-channel angular pressing, Mater.
Langdon, Principles of equal-channel angular pressing as a processing tool for grain refinement, Prog.

However, the addition of Ag also resulted in Cu-rich phases to precipitate at the grain boundaries of the as-cast material.
A continuous Cu-rich segregation zone appeared at the grain boundaries of the α-Al matrix.
This grain boundary segregated phase has also been reported by Chang et al [2] in permanent mould cast A201 and identified as CuAl2 (θ).
The chemical composition of the grain boundary phases (Points 2 in Table 2) reveals that it is most probably CuAl2 (θ), as also showed by Chang et al [2].
The spherical precipitates found within the α-Al grains (Points 3 in Fig. 3 and Table 2 for the as-cast samples) are most like the S-phase (Al2CuMg).

As shown in Fig.2(a), the microstructures of weld metal are mainly composed of acicular ferrite, fine-grained ferrite and proeutectoid ferrite.
The welding thermal cycles lead to peak temperature is different in different zone of HAZ, resulted in the grain sizes of austenite is different.
The grain of completely quenched zone which near weld is grew obviously, the microstructure is coarse martensite.
Mn can refine the grain, perform solid solution strengthening and the microhardness of the weld is increased.
From Fig.1 and Fig.2, it can be seen that using two kinds of welding wires for welding, the weld zones are both distributed a large number of acicular ferrite, which has high strength and toughness.

Inside the coarse β-grains, thin acicular precipitations of α(α'')-phase with a thickness of 130 nm are observed (Fig. 1b).
According to transmission electron microscopy, a grain-subgrain structure with an average element size of 0.7 μm is formed in the alloy [6].
Studies of the structure showed that as a result of aging in the grains and along the boundaries of the β-phase, secondary α-phase is released.
It was found that stress amplitudes (fatigue limit) in the ultrafine-grained alloy reaches a stress level of 800 MPa corresponding to number of cycles to failure of ~ 3.3 × 108.
Grain boundary diffusion and properties of nanostructured materials.

The precipitation of the second phase particles at the grain boundary or in crystal grain, the dislocation tangle and the dislocation pinning of the dispersion carbonide hinder the SSC cracks to propagate.
While over 110°C, the electrochemical corrosion in both the anode and the cathode is speeded up, and the crystal grains of corrosion products grow bulkily and irregularly, with some gaps between the grains (see Fig. 2(c)).
Fig. 6 (a) STEM and (b) TEM image of C100 steel (a) (b) It is easy to see that the second phase particles precipitating at the grain boundary or in crystal grain as well as the precipitation of carbonitride (Fig. 6(a)).
(5) The second phase particles precipitating at the grain boundary or in crystal grain, the dislocation tangle and the dislocation pinning of the dispersion carbonide hinder the SSC cracks to propagate.
Prevention of CO2 corrosion of line pipe and oil country tubular goods. 1984, Paper number: 289 [10] Ikeda A, Ueda M, Makai S.

Perlite colonies were formed inside austenitic grains, have both spheroid equiaxial, and slightly elongate form, average grain size is 1÷5 μm.
Thus, it could be confirmed, that fine recrystallized and poligonized initial austenitic grains in steel R2 and appearance ferrite at the grain boundaries in the steel R1 are the main structural difference of steel obtained by different technologies.
Wherever, huge number of cyclic contact (from 500 ths. to 1.5 mil. cycles) wagon wheels with rails could cause local micro plastic deformation, provided strain hardening and future micro destruction [5].
Thus, greater number of cycles will be needed for forming micro cracks in the steel R2 during exploitation, that gives higher potential of rails.
This stresses much bigger than the same at the contact surface or into the perlite grains.

The initial microstructures consisted of either course columnar grains for the 2 and 4%Mg alloys and dendritic columnar grains for the 8 and 10% Mg alloys.
The structure within the Al-Mg alloy can be clearly seen and consists of a number of needle-like particles and a more irregular light grey structure.
Fig.5 shows a second scan in the same sample as Fig.4 over a cell that contains two grains with a vertical grain boundary.
Fig 5(b) shows an EDS map for magnesium which indicates that there are a number of magnesium-rich particles on the grain boundary.
The magnesium seen in the grains in Fig.4 may have initially precipitated on grain boundaries but, due to the high processing temperatures and slow cooling rate, the grain boundaries may have migrated away from the magnesium precipitates.

Grain size was analysed using light microscopy (magnification of 1000-times).
It can be assumed, that this result is due to a large amount of carbides on the grain boundary preventing the growth of austenitic grains.
There is evident, that the number of carbides with dimensions less than 1 mm is much greater after SZT as compared with classic heat treatment for observed P/M steel Vanadis 30.
Austenitic grain size is G = 13 for all observed austenitizing times.
The number of carbides with dimensions less than 1 mm is much greater after sub-zero treatment as compared with classic heat treatment.