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The code numbers for the variables used in the Table 4 were obtained from the following equations: （1） （2） （3） （4） Where, r is the number of replication of level (r=3), m is the number of level (m=3), n is the number of total test (n=9) and T is the sum of the testing results.
Al) is columnar grains around periphery and equiaxed grains in the center.
For 316 stainless steel, the microstructure of spot welding joint is typical columnar crystals in nugget, and the grain size is very coarse, as shown in Fig.3.
The base material microstructure is shown in Fig.3 a, which is primary austeniten structure with isometric grain.
The heat affected zone of spot weld joint for 316 stainless steel shown in Fig.3 b is very narrow and the grain is almost no change compared with the base metal.

Fig. 7 illustrates the surface morphology of the specimens strained to 480% at strain rate of 10-3s-1 and temperature of 525oC, grain boundary sliding can easily be seen from the large number of grain boundary steps and off sets as shown in Fig. 7.
Some strain free grains replace the deformed grains.
Fig. 9 clearly shows emergence of recrystallized grains at grain boundary heterogeneities and variety of grain sizes, at high magnification.
Grain off-sets and grain separation due to GBS is clearly evident.
Gifkins: Effect of Grain Size and Stress Upon Grain Boundary Sliding, Metall.

The area fraction of deformed grains with specific orientations at each recrystallization stage was obtained by calculating the difference in the area fraction of all grains and that of the recrystallized grains.
Since the low mobility of high angel boundaries is significantly higher than that of low angel grain boundaries, with the annealing temperature increases from 680˚C to 800˚C, the nucleis and grains with lowly mobile grain boundaries are consumed by other highly mobile grain boundaries.
The driving force of grain migration is the stored energy difference between distorted grains and non-distortion grains, the migration orientation of grain boundaries is always the divergence orientation of curvature center and moves to distorted grains until the distorted grains were displaced by the non-distorted equiaxed grains.
The former is formed by a large number of {111}<110>rotating 30° around <110>crystal axis,the latter is formed by a large number of {100}<012>rotating 18.44° around <110>crystal axis.
The driving force of grain growth is difference between grain boundaries which is different from recovery and recrystallization,because the grains boundaries between grains with η-fibre orientation such as Goss component are the maximum,it can be seen that the intensity ofη-fibre texture is maximum.

Relative high (>8,5oC/s) cooling rate results spheroidal grain morphology.
Changing of: a) IMC layer thickness, b) grain numbers of Pb-Bi precipitates According to the image analysis measurments it can be concluded, that the area of Ag3Sn showed minimum at 1%Pb content.
The grain number of the Ag3Sn intermetallic compound showed no sensitivity to thermal cycles in a case of 1 or more wt% Pb content.
Changing of the Ag3Sn: a) area, b) number of grains b) a) Chen et al [17] investigated Sn3.5Ag0.75Cu (SAC) solder joint reliability under thermal cycling, They found that obvious coarsening of Ag3Sn particles in the solder bulk took place with increase of the number of thermal cycle.
The area and grain number of Ag3Sn IMCs correlate with Pb content: in case of Pb content ≥ 1wt% the area and the grain number of Ag3Sn intermetallic compound is smaller than in 0-1wt%Pb content samples.

Literatures 6 and 7 stated that the grains of conventional diamond wheels are easy to be pulled out and the wheels fail too early during grinding because the grains were only mechanically embedded in the matrix, resulting in short service time.
Details of the measure procedure of the protrusion hight of grains was reported in reference [9].
The number of diamond grits chosen to track the protrusion height of diamond grits in the experiment is sixty.
The number of whole diamond grits decreased rapidly in beginning phase, and the fractured, flat and break flat increased.
In spite of good metallurgical bonding, there will be no good wear performance if the diamond grain fractures or break flat, in which case diamond abrasive grains would be worn rapidly and should be restrained.

Recently, an impressive number of additive manufacturing processes are available.
A number of studies were designed for cold arc welding (СМТ).
In underlying layer 2 (Fig. 11 c, d), where recrystallization occurred twice, the size of the ferrite grain corresponds to number 10 and is the same in both longitudinal and transverse sections (13.4 ± 6.9 μm and 12.7 μm ± 6, 6, respectively).
As a result, the grain size decreases at the depth of 10 μm.
Grain sizes in layers from 4 to 1 are refined.

The bulk 2.7Y-TZP ceramic with an average grain size of 110 nm reached fracture toughness of 11.2 MPa·m1/2.
A nano-grained alumina/zirconia composite with an average grain size of 92 nm was obtained.
Grain sizes were determined by a linear analysis of SEM micrographs of the polished and etched (1100 °C for 1 h) surfaces.
An average fracture toughness and standard deviation for each sample were computed from the total number of fracture toughness values per sample (12 values).
At this temperature, the grain size remained in the nano-scale range [2, 4].

. %).The results showed that Si3N4 particulate has remain as foreign particles and precipitate at the grain boundaries thus improved the physical properties of the composite solder compared to monolithic solder alloy.
The lead-free composite specimens were polished and etched in a solution of 93%methanol + 5%HNO3 + 2% HCl for clear grains structure observation.
Si3N4 particles were seen well distributed between the grain boundaries.
Reinforcement concentration between the grains will tend to hold the grains, preventing from grain dislocation and retards the grain growth.
The Si3N4 particle’s number was increased with the addition of reinforcement in the grain boundry region.

Fig. 1 shows structurally the grain boundary of TiAl alloy with various lengths of micro pre-cracks.
Simulation Results when TiAl Alloy Grain Boundary is Provided with a Micro pre-crack of the Size of 6 Atoms.
As the temperature rises, so is the thermal motion of the TiAl alloy atoms, and the density distribution function peaks remain unchanged in number as well as in position, but their peak shortens and widens progressively.
As the temperature rises, so is the thermal motion of the TiAl alloy atoms, and the density distribution function peaks remain unchanged in number as well as in position, but their peak shortens and widens progressively.
Peak values are substantially higher, thus indicating higher atom energy, at the grain boundary than near it.

From the analysis of EPMA, La concentration mainly aggregates at the grain boundaries, which hinders the growth of columnar grains and prompts the transformation of microstructure from columnar grains to equiaxed grains.
As shown in Fig. 1, the grain sizes are refined with La addition.
On the other hand, with the rising of La content, the number of La-rich second phase particles increases.
Compared to sample 0#, a number of La-rich phase particles are presented in the dimples of the 1# copper alloys.
(2) The grain sizes of cast pure copper can be refined with small La addition.