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The corrosion products at the grain boundaries were found to be mainly some oxides.
The grain size was up to 8.0.
Almost all secondary cracks were growing along the grain boundaries (Fig. 5b).
It was surmised that main covered layer materials were a large number of completion fluid sediments and a small amount of certain oxides.
The microscopic grain boundary of the tempered martensite contained high carbide density, the high potential carbon rich region of grain boundary became the cathode, and the low potential carbon poor regions on both sides formed the anode.

Automation of Installations for Solar Drying of Grain Seeds and Fluidized Bed Technical Plants CERNĂIANU Corina1,a, CERNĂIANU Adrian1,b and STĂNCUȚ Eugenia1,c 1University of Craiova, Faculty of Mechanics, Bld.
Introduction Grain seeds: wheat, barley, oats, rice, maize, buckwheat, etc. which provide food for humans and animals, as well as the raw material of some industrial enterprises, have an average moisture content of freshly harvested grains ranging from 13% to 40%.
In the Machinery and Tools Research Laboratory, within the Faculty of Mechanics of Craiova, a type of experimental installation for the drying of grains using two alternative sources of thermal, solar or thermoelectric energy was designed, achieved and tested, depending on the atmospheric conditions or the site where the drying process occurs [2,3,4].
For hot and cold air traffic, two external fans (34) and (38) supported by wood bases (35) and (37) are used on the various supply circuits of the installation model, as well as a series of tubes intended for the two main circuits: the rock bed heating and the fluidized bed drying of the grains.
Manuscript number 1292.

In some cases the microbands were also initiated near hard martensite or RA crystals and did not traverse the entire PF grains, whereas in the majority of the cases the entire PF grains contained microbands.
The fatigue data for AR, 10%PS and 20%PS TRIP steel (Fig. 4a) show, for a constant strain amplitude, an increased number of cycles to failure with increasing pre-strain.
At the same time, the numbers of reversals for the DP steel are lower than for the TRIP steel for all conditions.
In this condition, the deformation bands cross the grain boundaries and propagate through several grains and in multiple directions (Fig. 5e).
Fig. 4 Strain amplitude vs. number of reversals to failure for asreceived (AR), pre-strained (PS) and pre-strained/bake hardened (PS/BH) conditions (a) and stress amplitude vs. number of strain reversals for a constant strain amplitude of 0.006 (b) for the studied steels.

(3) Shapes of scratches on the ground surface are the same as those of grain tips.
The elastic deformation of the workpiece and grain tips is neglected.
Subscripts i and j of are the number of cutting tips and the number of cutting times, respectively.
Point B, C and E are the tip point of abrasive grain.
Fine-grain wheels were employed due to increasing cutting tip densities.

Ferrite grain size measured by ASTM method is found to be 19µm.
Once the cracks nucleate, they grow with number of cycles.
The presence of intergranular fractures suggests that grain boundaries have been weakened by somehow.
(a) (a) (b) (b) present on intergranular facets suggest that there is no jerky change in crack propagation rate when the crack front crosses any grain and enters inside the grain boundaries.
Presence of striation marks on both the transgranular and intergranular facets qualitatively suggest that fatigue crack growth on grain boundaries and within the grains followed repeated cycles, i.e., there might be no significant (jerky) change in the crack propagation rate when the crack front left the grains and entered into the grain boundaries and this is a qualitative information.

The average grain size of such sand should be 0.25 - 0.30 mm.
The average grain size of such sand should be 0.25-0.30 mm.
The number of points of contact between the grains of sand decreases, resulting in a reduced form strength.
Classification of sand grains by shape.
The sphericity of grains of sand can vary from medium to high, the shape of the grain - from semicircular to round.

Then the number and density of electron scattering-source in matrix-lattice will increase, and the mean free path of conduction electrons will decrease, resulting in the rise of electrical resistivity[6].
As temperature increases, atomic diffusion velocity will intensify sharply so that the number of bulky dendrite decreases in alloy to expand the degree of saturation of solid solution (Fig.4(c)).
When temperature rises to 520˚C, the phenomenon of dendritic segregation will disappear at a large extent, the composition of alloy is distributed uniformly and the grain boundary come to narrow, but there are still some undissolved granular materials existed in the grain(Fig.4(d)), and the degree of saturation is to further enlarge.
Alloy grains begin to produce some melting pellets to appear the burned structure at 535˚C(Fig.4(e)), and grains burn more severely by continuing to raise the temperature(Fig.4(f)).
From these pictures, solute atoms and strengthening phases dissolve in the aluminum matrix gradually along with the extension of time, and grains also grow continuously.

Ways of Rare earth elements of the reinforcement on 7075 Al alloy are mainly fine-grain strengthening and rare earth compounds of second phase strengthening[1,2].
In addition, in this experiment uses two-stage aging treatment and the aging process , the supersaturated crystallology was decomposed and precipited intermetallic, diffusing distribution in grain or grain boundary that will greatly increase the strength [6], so table 2 test results is the concrete representation.
Owing to effect of the rare earth refine grains, so the intensity of alloy is increased, at the same time, the plastic will be not damaged [7,8].
But the rare earth compound′s particle will becomes bulky, appears needle enrichment phase, separates the matrix grain, brings stress concentration while existing on grain boundary and deteriorates 7075 Al alloy′s comprehensive mechanics performance when the rare earth elements added too much more.
Atapek, Effect of aging temperature and of retrogression treatment time on the microstructure and mechanical properties of alloy AA 7075,Metal Science and Heat Treatment,Volume 49, Numbers 9-10, 2007,9

Background There are a number of commercially available DSS alloys that are best categorized in terms of their Cr and Ni equivalent concentrations.
Hardening in the ferrite grains was expected due to the α-α' phase separation.
No hardening trends were observed in the austenite grains.
The microhardness measurements are reported in terms of the Knoop hardness number, HK, which is the ratio of the load applied to the indenter (kg), to the unrecovered projected area of the indentation (mm2).
Line scans across the grains were acquired with a 1 micron diameter beam and a beam current of 50 nA.

Metallographic analysis proving a kind of hot crack is cause by the precipitate in grain boundaries.
Introduction The direct chill (DC) casting process (Fig. 1) has been used to produce copper alloy cylindrical ingots during the past half a century, because it has a number of advantages: (a)Ingots have a more compactness organization owing to the high velocity of crystallization; (b) DC casting process can avoid shrinkage problems effectively due to a directional solidification along the casting direction; (c) DC casting process can produce different type of ingots via replacing molds [1].
Metallographic images shows that the crack is along grain boundaries, additionally there is precipitate in grain boundaries.
The precipitate in grain boundaries decreases CrZrCu alloy intensity.