Search results

Due to the large number of possible applications, several billion micro parts are produced every year.
The average grain size is 18 µm in rolling direction (RD), 14 µm 90° to the RD and 5 µm in sheet thickness direction.
Cu-OFE-HT, DC04 and AA6014-T4 have uniform cubical grains with no measurable anisotropy in the micrographs (Fig. 1).
The average grain size is 41 µm (Cu-OFE-HT), 33 µm (DC04) and 21 µm (AA6014-T4).
While the other studies assume ductility, strength or grain size as the cause, it was proven that the strain hardening exponent is the decisive material parameter.

Each element represents a subdomain of a grain that transforms according to the kinetics found in the measurements.
Each element represents a subdomain of a grain that transforms according to the kinetics found in the measurements.
Thus the number of domains having transformed evolves with time as can be seen in Figs. 5a and b, with the austenitic elements coloured blue and red ferrite elements.
A clear influence of recrystallisation on grain refinement in the intercritical two-phase field could be found.
Eghbali, Study on the ferrite grain refinement during intercritical deformation of a microalloyed steel, Mat.

The results show that the thin films exhibited a polycrystalline structure in the form of columnar grains, and only b.c.c.
The surface is very fine and smooth, and there are no obvious grain boundaries and other defects.
This shows that the average grain size of the films increases with the increase of Ti content in the films.
These islands structure grow with the increase of the number of atoms, the occurrence of "island" and "island" between the connection, and hence the W-Ti film layer structure and the layered structure of W-Ti thin film is formed [9,10].
The as-deposited films exhibit a polycrystalline structure in the form of columnar grains, and the planeness of surface is pretty high.

Numerous deepening pits overspread from the protuberant grain faces to the grain boundaries, along with more quickly diminishing pyramidal crystallites.
This result reveals that at a constant pulse duration enhancing the discharge current can result in the increase of deepening etch pits overspreading within the protuberant grain face to the grain boundaries, along with the diminishing of pyramidal crystallites.
Further analysis of these protuberant grains, we can find its spongy configuration as presented in Fig. 4(d).
It is found that only the tips of diamond grains were smoothed after mechanical polishing for 100 min.
It reveals that the full width half magnitude (FWHM) is less than 10 wave numbers at 1332 cm−1, which shows a very good quality of polished diamond film accompanying a great hardness and no microcracks [16].

For instance, the addition of boron and an increase in the temperature during the solubilization stage, to reach the α + β phase field, can inhibit the growth of α grains due to the presence of β grains [12, 17].
In this figure, a predominant amount of γ grains are enclosed within a lesser α2 matrix.
However, in HT1 and the as-received material, these particles were observed to be smaller and more evenly distributed, while samples from HT2 and HT3 treatments exhibited larger, more acicular TiB2 particles, though in fewer numbers.
Specimens from HT2, where globulization was observed, showed an actual increase in the number and length of TiB2 particles, giving them a more acicular appearance.
Experimental study of the effects of heat treatment on microstructure and grain size of a gamma TiAl alloy.

However, the grains become smaller and more uniform with x increasing.
And the number of pores (porosity) first decreases and then increases.
From the images we can get that when the amount of BiFeO3 added is below 0.002mol, BiFeO3 has an positive effect on the growth of grain and the sizes of grains are still of micron order, and the grain boundary is clear.
While x>0.002, the average size of grain falls rapidly even to several hundreds of nanometer and the boundary is indistinct, and many individual pores exist in the grain boundary.
And the average size of grain would be enlarged.

Some recrystallized grains can also be observed due to recrystallization of the broken grains during the hot rolling process.
In Fig. 3b, lots of low angle boundaries are observed in the interior of the grains.
The statistical result displays 72.3% grain boundaries less than 20 degree (Fig. 3c), indicating that numerous grains are broken up during hot rolling.
The EBSD images in Fig.11 show that the samples are recrystallized after continuous annealing because of the existence of a number of fine equiaxed crystal grains, but some sub-structures still exist in the interior of the grains.
In addition, the recrystallized grain size decreases with the increase of rolling reduction.

The results show that the b-Sn in the alloys precipitates mainly in the form of strips and blocks on the grain boundaries of α-Al phase or the interface of silicon and α-Al phases.
The hypereutectic Al-20Si alloy without Sn consists of poly-hedral or blocky primary silicon phase distributed in a matrix that comprises α-Al grains and needle-like eutectic Si particles (Fig. 1a).
According to atomic number sequence, the white phases in the matrix are b-Sn.
With adding 1% Sn to the alloys, b-Sn precipitates mainly in the form of thin strips and small blocks on the grain boundaries of α-Al phase (Fig. 2a); with 3%Sn addition，b-Sn blocks became large (Fig. 2b).
Conclusions (1) Adding Sn to hypereutectic Al-20Si alloys makes poly-hedral or blocky primary silicon phase become slightly small and needle-like eutectic Si slightly short; (2) With adding 1% Sn to the alloys, b-Sn precipitates mainly in the form of thin strips and small blocks on the grain boundaries of α-Al phase; with 3%Sn addition，b-Sn blocks became large.

Experimental part 1.1 The experiment materials PPS: grain size of 40 um, density of 1.17 g/cm3.TPI: grain size of 20 um, density of 1.35 g/cm3.TLCP: grain size of 16 um, density of 1.6 g/cm3.Graphite: grain size of 16 to 20 um.25# steel: rectangular in shape and the size for 120 * 120 * 3 mm. 1.2 Sample preparation 1) PPS, TPI, Graphite and TLCP were dried respectively in the drying oven. 2）The dried PPS of 45 to 67 %wt, TLCP of 10 to 20 %wt, TPI of 20 to 30 %wt, Graphite of 3 to 5 %wt were weighed.
Using TM2 type eddy efficient mixing machine to mix together . 3) The mixed ingredients were taken into a twin screw extruder for granulation. 4) 25 # steel plates were named from number 1 to 6.
The thickness of composite plastic layer and numbers are showed in table 1.
Table 1 The thickness of composite plastic layer number 1# 2# 3# 4# 5# 6# thickness of plastic layer 1 mm 1.5 mm 2 mm 1 mm 1.5 mm 2 mm 1.3 Performance test According to GB3960-1983, friction and wear test was tested in the M-200 type friction and wear testing machine.
Table 2 Bond strength Sample Numbers 1# 2# 3# 4# 5# 6# Bond strength/ MPa 9.78 9.13 6.37 15.27 20.33 14.45 With the increasing thickness of plastic work layer, the 1#, 2# and 3# test plates bond strength between metal and plastic layer was decreasing.

Titanium alloys have a number of features which make them attractive for use in aerospace, marine and chemical engineering, biological engineering, etc., due to their advantage of low density, high strength, and excellent corrosion resistance and biocompatibility.
Closed spherical pores, which are located inside the grains, and lenticular pores, some of which are probably open pores, are located on the grain boundaries.
The as-extruded Ti-64 rod has fine DRX grains which can be seen in Fig. 2f.
At the very beginning, the pores retard grain growth, but later on, the grain boundaries eventually break away from the pores, leaving them isolated in the grain interior.
An obvious dynamic recrystallization has occurred in the Ti-6Al-4V alloy rod after extrusion, giving a refined grain structure with grain size in the range of 20 to 50μm.