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21.
高硬度耐磨电弧喷涂管状丝材的研究 总被引:2,自引:0,他引:2
利用自熔性合金与非晶态材料的特点,研制了Fe—B系管状丝材作为电弧喷涂材料,其形成的涂层具有良好的结合强度、低的孔隙率、高的硬度和耐磨损性能。 相似文献
22.
Hamdy F. M. Mohamed 《应用聚合物科学杂志》2008,108(2):1307-1313
Coincidence Doppler broadening of annihilation radiation (CDBAR) and Vickers hardness techniques were performed to study pure Al2O3, pure polyvinyl chloride (PVC), and doped PVC with different concentrations of Al2O3 (10–50%). The CDBAR ratio curves with respect to pure PVC were presented and reflect the momentum distribution of all the samples. The peak around 14.5 ×10?3 moC in the CDBAR ratio curves suggests a large contribution of positron annihilation with the Al2O3. There is a linear correlation between the height of this peak and the Al2O3 concentration. The S‐ and W‐parameters were extracted from the CDBAR spectra and increase with increasing the Al2O3 concentration showing discontinuity at 30% of Al2O3 concentration on PVC. The present data confirmed that there is no positronium formation in pure Al2O3 as a result of smaller S‐parameter. The Vickers hardness increases with increasing the Al2O3 concentration in PVC showing a linear dependence with two different slopes depend on the Al2O3 concentration range. A correlation between the Vickers hardness (macroscopic data) and the W‐parameter (microscopic data) was observed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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H. Hoedlmoser M. Moll J. Haerkoenen M. Kronberger J. Trummer P. Rodeghiero 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2007,580(3):1243-1249
Epitaxial (EPI) silicon has recently been investigated for the development of radiation tolerant detectors for future high-luminosity HEP experiments. A study of thick EPI silicon diodes irradiated with protons up to a fluence of has been performed by means of Charge Collection Efficiency (CCE) measurements, investigations with the Transient Current Technique (TCT) and standard CV/IV characterizations. The aim of the work was to investigate the impact of radiation damage as well as the influence of the wafer processing on the material performance by comparing diodes from different manufacturers. The changes of CCE, full depletion voltage and leakage current as a function of fluence are reported. While the generation of leakage current due to irradiation is similar in all investigated series of detectors, a difference in the effective doping concentration can be observed after irradiation. In the CCE measurements an anomalous drop in performance was found even for diodes exposed to very low fluences in all measured series. This result was confirmed for one series of diodes in TCT measurements with an infrared laser. TCT measurements with a red laser showed no type inversion up to fluences of for n-type devices whereas p-type diodes undergo type inversion from p- to n-type for fluences higher than . 相似文献
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气门用4Cr9Si2钢调质工艺研究 总被引:1,自引:0,他引:1
采用正交试验 ,研究了 4Cr9Si2钢的淬火温度、回火温度与组织、硬度间的关系 ,得出了最佳的工艺参数 (10 10℃淬火 ,6 0 0℃回火 )。实际生产表明 ,采用此工艺后 ,断裂现象基本消除 ,气门的热处理质量有了明显提高。 相似文献
28.
The care of the world environment poses many challenges to the proper disposal of mineral wastes. Particulate wastes can be used to modify the properties or lower the cost of polymers. The influence of an iron–silica rich waste on the hardness of an epoxy resin is evaluated in this work. It is shown that the hardness values are polymer dominated for volume fractions of waste lower than 0.30, but for higher volume fractions a useful increase in the hardness numbers can be achieved. The coarser the particles are the more heterogeneous is the microstructure of the composite. Nevertheless, particulate rich layers increase the hardness of the material several times. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2178–2184, 2002 相似文献
29.
Local stress and strain variations in the deformation zone can be ascertained by measuring hardness. Hardness is correlated
with strain and stress. The expressions discussed later are useful in determining the local variations in stress and strain
from hardness measurement. It is a simple method compared to visioplasticity. One can estimate the forces required for a forming
process. It helps in the choice of equipment, design of tooling and selection of lubricant for the particular process. 相似文献
30.
In the initial part the change of microstructure for steel X20 CrMoV 121 is discussed in terms of the distribution of carbide precipitates and its effects on accelerated creep resistance and hardness are presented. In the following, experimental results of microstructure and accelerated creep resistance are presented for the steels X20CrMoV 121 and P91 annealed for up to 8760 hours at 650°C and 750°C before the testing. A similar evolution of the distribution of carbide particles of a size above 102 nm is found for both steels, while the accelerated creep resistance is diminished much stronger for the steel X20CrMoV 121. This difference is due to a greater stability of NbC than that of VC precipitates, both related to the evolution of the chemical composition of complex chromium, molybdenum and iron carbide particles. 相似文献