In the present paper, tensile experiments were carried out on 5CrMnMo in a wide range of temperature (25°C-537°C) and strain rate, and the corresponding stress-strain curves were obtained. The experiment res...
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In the present paper, tensile experiments were carried out on 5CrMnMo in a wide range of temperature (25°C-537°C) and strain rate, and the corresponding stress-strain curves were obtained. The experiment results show that the mechanical properties of 5CrMnMo are rate independent under room temperature. When the temperature increases, strain-rate-hardening and temperature-softening effects come into evident on the modules E, the yield stress σs and the tensile strength σb. The decreasing of strain-hardening-rate and the creep behavior also emerge and these phenomena become obvious with increasing temperature and decreasing strain rate. As the result, the unstable strain Εb decreases, while the percentage elongation after fracture δ50 increases with increasing temperature;S50 decreases with increasing strain rate. At high temperature and low strain rate, the lath martensite reorientates to the loading direction.
Lead Iodide (PbI2) crystal is a promising material for room temperature nuclear radiation detectors, characterized by its large average atomic number and wide band gap. In this paper, the Lead Iodide (PbI2) poly-cryst...
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Lead Iodide (PbI2) crystal is a promising material for room temperature nuclear radiation detectors, characterized by its large average atomic number and wide band gap. In this paper, the Lead Iodide (PbI2) poly-crystal has been successfully synthesized directly from Pb and I2 by two-zone vapor-transporting method (TVM). PbI2 single crystal with three different colors were prepared using Vertical Bridgman Method (VBM). By adjusting the position of ampoule in a suitable temperature gradient to prevent iodine atoms from the crystal inside, the yellow PbI2 single crystal with good quality can be prepared.
For determining the isothermal section of the R-Fe-Co pseudotemary system with R&le33.3 at.% (R = Sm0.5Ho0.5) at 800°C, different components of 39 samples of R-Fe-Co alloy series are melted in filling argon g...
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For determining the isothermal section of the R-Fe-Co pseudotemary system with R&le33.3 at.% (R = Sm0.5Ho0.5) at 800°C, different components of 39 samples of R-Fe-Co alloy series are melted in filling argon gas's arc furnace that is controlled by magnetism. Every sample phase is known by optical microscopy, X-ray diffraction analysis and electron probe microanalysis. Results show the isothermal section contains 9 single-phase regions, 14 two-phase regions and 6 three-phase regions. There are 7 intermetallic compounds and no 5:19 phase in the section.
An in-situ reflectance monitor was used to improve the reproducibility and controllability of crystal growth by MBE (Molecular Beam Epitaxy). A DBR (Distributed Bragg Reflector) was grown using the in-situ monitor. Th...
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The effect of sub-critical heat treatment on microstructure and properties of 16Cr-2.5Mn high chromium white iron are studied in this paper. The hardening mechanism and abrasion resistance are analyzed by using transm...
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The effect of sub-critical heat treatment on microstructure and properties of 16Cr-2.5Mn high chromium white iron are studied in this paper. The hardening mechanism and abrasion resistance are analyzed by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and M200 wear test machine. Results show that Cr and C solid-dissolved in the supersaturated austenite precipitate as (Cr, Fe)23C6. Thereby the retained austenite transforms into martensite in cooling process which results in secondary hardning. Long holding time would cause in situ transformation of (Cr, Fe)23C6 to M3C carbides in the process of sub-critical treatment and the matrix transforming to pearlitic structure, Which would cause hardness and abrasion resistance decreasing. The alloy would obtain the highest hardness and optimal abrasion resistance when the content of retained austenite is 10%.
PV modules have a problem that the power generated decreases with the rise of the PV module temperature. In order to solve the problem, we recently developed a new PV cooling device utilizing siphonage. In the first r...
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The main results obtained are as follows: (1)New ultra-smoothness grinding method is useful for finishing the cemented carbide to the ultra-smoothness surface. (2)At the normal feed of 10 micro-meter/rev, the 2D surfa...
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ISBN:
(纸本)1887706399
The main results obtained are as follows: (1)New ultra-smoothness grinding method is useful for finishing the cemented carbide to the ultra-smoothness surface. (2)At the normal feed of 10 micro-meter/rev, the 2D surface roughness becomes below 20nm(Rz). The surface roughness increases steeply and transiently until the normal feed of 30 micro-meter/rev and keeps about 100nm(Rz) over the normal feed of 30 micro-meter/rev. (3)The 3D surface roughness increases with increase of parallel feed. The increase rate is small. Even at fp=50 micro-meter, the 3D surface roughness becomes below 50nm(Rz).(4)The 3D surface roughness of cemented carbide formed using the suitable grinding condition attains about 25nm(Rz) or 2.5nm(Ra).
In our previous researches, the newly devised ultra-smoothness grinding method is proposed and ascertained to be useful for finishing fine ceramics to the ultra-smoothness surface below 30 nm(Rz) or 5 nm(Ra). In the r...
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In our previous researches, the newly devised ultra-smoothness grinding method is proposed and ascertained to be useful for finishing fine ceramics to the ultra-smoothness surface below 30 nm(Rz) or 5 nm(Ra). In the research, the influence of dept. of cut on ultra-smoothness grinding of a silicon carbide ceramic is examined. The dept. of cut ranges from 5 micro-meters to 1 mm. In the ultra-smoothness grinding method, it is found possible to finish the silicon carbide ceramic to high smoothness surface at even the dept. of cut of 1 mm using metal bonded diamond wheel of coarse grain size of #140.
Micro-TIG arc welding is a low-cost joining process for micro and small fabrications. This paper investigates the electrical signal features of microarc for the hybrid and high-frequency pulsed processes under differe...
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Micro-TIG arc welding is a low-cost joining process for micro and small fabrications. This paper investigates the electrical signal features of microarc for the hybrid and high-frequency pulsed processes under different weld penetrations. The time domain analyses show that the arc voltage is always lower for the fully penetrated weld particularly during the background current time of immediate frequency pulse. Also, the average voltage-current (V-I) graph plotting approach reveals that the position, shape and changing rate of the V-I hysteresis loop markedly differ with weld penetration in addition to pulsating frequency and pattern. These results thus demonstrate that microweld penetration can be characterized by the use of arc electrical signal features.
Electromigration in solder joints causes a void formation between intermetallic compounds (IMC) and solder at the cathode. The effect of electromigration in mechanical test of Cu wires joined by solder was performed. ...
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