Search results

(2) Where T * is the maximum temperature rise due to the grinding heat above the initial temperature T0,  wck is the workpiece thermal contact coefficient, the parameter considering the effect of the thermal number and transient behavior during cutout had been defined in [3] by Guo. w is the energy portion to the workpiece, while the composite model presented in [4] was used in this study.
And based on Hahn's model for grain and workpiece surface interaction, the relation between hw and hs can be written as Eq.5
(5) Where kg is grain thermal conductivity, ech is limiting chip energy, and r0 is wear flat radius.

Rudd and Broughton [2-3] develop an approach that is called coarse-grained molecular dynamics(CGMD).
The basic idea in CGMD is that a coarse-grained energy approximation that converges to the exact atomic energy is utilized to derive the governing equations of motion.
(n)l denotes the atom number included by a generalized particle. 0m and 0a are atomic mass and lattice constant respectively.

Fig. 1 Creep curves of samples A1-A2 at 1300°C, 0.2MPa Fig. 2 Creep curves of A1-A2 after 25h at 1300°C, 0.2MPa Table 3 Coefficient of the creep equation after 25h Number A1 A2 k 0.000011 0.000629 d 0.086570 0.163570 (a) (b) Fig. 3 Appearance of the crept samples: (a) A1, (b) A2 Fig. 4 XRD patterns of the crept sample Surface morphology of samples A1 and A2 after creep test were shown in Figure 3, apparent delamination of the sample can be seen, i.e. the oxide layer, transition layer and the non-oxide layer, wherein the thickness of the oxide layer was very small, effect to the creep resistance of the sample can be ignored.
Grain boundary phase and microstructure of the material determines its creep properties [8-9].
Slip along the direction of crystal and particle diffusion along grain boundaries led likely to pure corundum materials poor creep resistance.

The microstrcture is made of tissue morphology and tiny grains, without carbide liquid chromatography, banded carbide and other defects.
The structure of inner ring is made of block but not dissolve carbide plus acicular tissue, a large number of carbide exist regularly in acicular structure, as shown in Figure 4.
Carbide and ferrite grain are distributed about 57° angle with the shaft.

Thot is the temperature at hot side. n is numbers of a pair of Bi2Te3 and Sb2Te3.
Ultrafine grains always occurred in this area due to recrystallization.
The average grain size increased with decreasing deformation rate of aluminium [7, 8].

Introduction Hot blast furnace was widely applied in late 1970s as important process equipment for many industries, such as the heating, grain drying, food process and so on [1].
The total number of the heat exchange tubes (diameter isφ60mm ) in the stove is ninety-eight.
Duan: Grain Storage No.4 (2005), p. 40 In Chinese [3] Z.W.

Wave number (cm -1) Fig. 1.
The grain size of apatite found in the specimen heat-treated at 600 o C was about 50 nm while those found in the specimen heat-treated at 1000 oC was about 1 µm, respectively.
The grain size of the apatite granules heat-treated at 1000 o C was about 20 times bigger than those heat-treated at 600 oC.

The deformation of magnesium alloys is extremely orientation dependent due to its hcp crystallographic structure and the limited number of available slip systems at room temperature.
If the original grains in the compressed specimens have their basal planes oriented perpendicular to the compression direction, crystallographic orientation in that position is unfavourable for basal slip.
Even if the stress level is high enough to initiate the prismatic slip, the CRSS on prismatic planes is practically zero due to new grain orientation.

The grain grows up obviously as heating temperature increases (≤ 700℃), there the hardness appears to reduce.
It is found that α phase becomes large obviously as the increase of the holding time, there appears a large number of martensite as well.
(2) There only occurs recrystallization and grain growth of α phase lower than 700℃, so the hardness decreases as the increase of temperature.

It is evident that the Si atoms are interacted with SiO2 forming SiO(g) thin layer along the grain boundaries.
As the temperature risen up, the SiO(g) gas is sucked into the pump, leaving with a large number of pores [5].
[ 6] Robertson, W.M., THERMAL ETCHING AND GRAIN-BOUNDARY GROOVING OF SILICON CERAMICS.