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111.
HUANG Yi LIN Xuerong XU Jun Institute of Metal Research Academia Sinica Shenyang China HUANG Yi Associate Professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1990,3(10):277-283
The infrared emission of a high pressure vessel steel and two thin wall pressure vessel modelshave been investigated by use of vibro-thermography.The experimental infrared cracklengths were found to be agreed closely with the optical values during fatigue process.A possi-ble nondestructive testing method used to evaluate the pressure vessel has been given. 相似文献
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The synergistic influence of prior-austenite grain size and silicon content of 9Cr–1Mo steel on the resistance to scale spallation has been studied in air at 773 K (for 500 hr) and 973 K (12 hr). Two steels, irrespective of their grain size and Si content, did not show spallation during oxidation at 773 K. Spallation occurred at 973 K, and fine-grain steels exhibited less spallation resistance than coarse-grain ones (in low-as well as high-Si steels). Among the four possible combinations of grain size ans Si content, the steel with low Si and fine grains showed least resistance to spallation, while the steel with high Si and coarse grains showed the best resistance. Spallation was found to initiate in the areas adjoining the oxide ridges formed at the alloy grain boundaries. Oxide scales at the ridges and within the grains were analyzed by scanning electron microscopy (SEM/EDX) and secondary-ion mass spectrometry (SIMS). These analyses suggest depletion of silicon from the areas adjoining grain boundaries, resulting in thicker scaling that triggers spallation in such areas. For similar grain-size materials, the necessary thickness for spallation was attained earlier with low-Si steel rather than in high-Si steel. 相似文献
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Chloride rich reinforced concrete prisms were coupled to chloride-free prisms and exposed to diurnal and seasonal temperature cycles typical of those found in the UK. Acoustic emissions (AE) and galvanic currents were continuously monitored and correlated with ambient temperature. AE and galvanic currents were found to emulate the evolution of temperature in the diurnal cycles, although no specific relationship between AE and galvanic current could be obtained. The influence of seasonal variations in galvanic current had no obvious influence on AE Energy per second over the range of corrosion rates studied. The findings suggest that AE is more sensitive to short term (diurnal) changes in corrosion rates than the longer (seasonal) effects. It was hypothesised that this is due to transitory changes in the internal microclimate of the concrete. 相似文献
117.
针对普通声发射(AE)检测仪缺乏源定位功能,开发了计算机辅助AE源检测定位系统,并详细论述了该系统的组成、接口、源定位算法和程序、剔除噪声等问题 相似文献
118.
Masamitsu Watanabe Etsuko Toyoda Toshihiro Ichino Yasuhiro Higashi 《Corrosion Science》2007,49(2):766-780
Copper plates were exposed under sheltered outdoor conditions for up to one year, starting in September 2001 in Musashino City, Tokyo, a suburban area. Following various periods of exposure, the patinas on the plates were characterized to investigate their evolution by using X-ray fluorescence analysis, X-ray diffraction, field emission scanning electron microscopy, and glow discharge optical emission spectroscopy. The difference in the roles of sulfur and chlorine in the early stages of copper patination were identified by analyzing the depth profiles of these two elements. Sulfur was found on top of the patina as cupric sulfates such as posnjakite (Cu4SO4(OH)6 · H2O) or brochantite (Cu4SO4(OH)6). Brochantite appeared only after 12 months of exposure. In contrast, chlorine was found on the surface after only one month of exposure. It gradually penetrated the patina as the exposure period lengthened, forming copper chloride complexes. Chloride ions accumulated at the patina/copper interface, forming nantokite (CuCl), which promoted corrosion. 相似文献
119.
Tae-Sik Kim Young-Je An Kwang Ho Kim Won-Sub Chung Young-Rae Cho 《Metals and Materials International》2006,12(4):339-343
The effect of the dielectric constant (k) of bonding materials in a screen-printed carbon nanotube (CNT) cathode on the field
enhancement factor was investigated for high-efficiency CNT cathodes using the ANSYS software. The values obtained by a simulation
study were compared to the experimental results obtained for screen-printed CNT cathodes. The field enhancement factor increased
as the dielectric constant decreased, reaching a maximum value at a dielectric constant of 1, the value for a vacuum. The
findings indicate that the larger sheet resistance of the bonding materials, after the firing process, can be attributed to
the larger emission current of the CNT cathode. From these results, it was concluded that the best bonding materials for screen-printed
CNT cathodes should have a low dielectric constant and a high sheet resistance. This finding can be used as criteria for selecting
bonding materials for use in CNT pastes for highly efficient CNT cathodes. 相似文献
120.
采用浸涂及烧结工艺制备了锌铬膜防腐涂层,用辉光放电光谱分析和纳米压痕/划痕试验技术对其成分和力学性能分别进行了深度剖面分析,并探讨了涂层组成对防腐和力学性能的影响。结果表明,各元素随深度呈不同的分布状态和变化趋势,并与烧结过程相关,硬度、弹性模量的深度分布与元素的深度分布相对应,膜层有较低的失效临界载荷。 相似文献