ZHENG Zhi WU Weiwen GUO Jianting ZHU Yaoxiao Institute of Metal Research
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Academia Sinica
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Shenyang
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China Institute of Metal Research
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Academia Sinica
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Shenyang 110015
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China
金属学报(英文版)
Many compressive and tensile tests showed that the room temperature ductility of boron-free Ni_3Al alloy may be markedly improved by a moderate addition of Zr.The ductility of the stoichiometric Ni_3Al and even slightly enriched with Al,may be improved fairly between 400 —600℃,which behaves much better if Zr is added together with B.However,the high tem- perature ductility of Ni_3Al alloys containing Cr may be significantly increased by Zr which segregates slightly along grain boundaries.Thus,the toughening mechanism of Zr alloying seems to be different from that of B addition.
关键词:
Ni_3Al
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MA Zongyi YAO Zhongkai Harbin Institute of Technology
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Harbin
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China
金属学报(英文版)
The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure
关键词:
composite
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Corrosion
This paper introduces the design of a localized corrosion rate monitoring instrument that can monitor and evaluate the maximum and stable localized corrosion rate of a nonpassivable metal in a corrosive environment by measuring the current density in a corrosion sensor with an occluded anode.
关键词:
instrument;localized corrosion rate;monitor
李铂
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周建江
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夏伟杰
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吴连慧
液晶与显示
doi:10.3788/YJYXS20142904.0605
直线是机载座舱显示画面中最基本的图元,其显示质量对于整个画面的显示效果影响较大,尤其是小角度下直线显示的“麻花”现象一直是影响显示效果的关键问题之一.为了提高小角度下直线的显示效果,本文提出了一种基于Wu算法的亮度渐变改进算法.该算法通过渐进地展现直线从轴方向上的亮度变化过程,减少亮度畸变,有效地改进了显示效果.通过Matlab仿真和FPGA实现,验证了该算法反走样后的小角度直线显示效果明显优于其他算法,而且结合中点画线法后,绘制时间与Wu算法相当.同时该算法还可改善大角度直线和圆弧的显示效果,消除了大角度直线的边缘锯齿,解决了圆弧在小角度部分的虚化问题.因此本文算法可用于对实时性和显示效果要求高的机载座舱显示系统,以缓解飞行员的视觉疲劳.
关键词:
座舱显示
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反走样
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改进Wu算法
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小角度
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FPGA实现
中国腐蚀与防护学报
N。1Atmospheric Corrosivlty for Steels………………………………………………… .LIANG Caideng HO[I i。-tat（6）Caustic Stress Corrosion Cr。king of Alloy 800 Part 2.The Effect of Thiosul执e……………………………………… KONG De-sheng YANG Wu ZHAO Guo-zheng HUANG De.ltL。ZHANG Yu。。he CHEN She。g-bac（13）SERS slid E16CttOCh6iniC81 Stlldy Of Illhibit1Oli M6ch＆tllsth Of ThlollY68 Oil ITOll ID H....
关键词:
Juhua HUANG
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Jinjun RAO
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Xuefeng LI
材料科学技术（英文）
Sheet metal forming is widely applied to automobile, aviation, space flight, ship, instrument, and appliance industries. In this paper, based on analyzing the shortcoming of general finite element analysis (FEA), the conception of parametric finite element analysis (PFEA) is presented. The parametric finite element analysis, artificial neural networks (ANN) and genetic algorithm (GA) are combined to research thoroughly on the problems of process parameters optimization of sheet metal forming. The author programs the optimization scheme and applies it in a research of optimization problem of inside square hole flanging technological parameters. The optimization result coincides well with the result of experiment. The research shows that the optimization scheme offers a good new way in die design and sheet metal forming field.
关键词:
Sheet metal forming
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J.Q.ZHANGD.J.YOUNG
中国腐蚀与防护学报
Metaldusting attacks iron, low and high alloy steels and nickel-or cobalt-base alloys by disintegrating bulk metals and alloys into metal particles in a coke deposit. It occurs in strongly carburising gas atmospheres (carbon activity aC>1) at elevated temperatures (400 ℃~1000 ℃). This phenomenon has been studied for decades, but the detailed mechanism is still not well understood. Current methods of protection against metal dusting are either directed to the process conditions-temperature and gas composition-or to the development of a dense adherent oxide layer on the surface of the alloy by selective oxidation. However, metal dusting still occurs by carbon dissolving in the base metal via defects in the oxide scale. The research work at UNSW is aimed at determining the detailed mechanism of metal dusting of both ferritic and austenitic alloys, in particular the microprocesses of graphite deposition, nanoparticle formation and underlying metal destruction. This work was carried out using surface observation, cross-section analysis by focused ion beam and electron microscopic examination of coke deposits at different stages of the reaction. It was found that surface orientation affected carbon deposition and metal dusting at the initial stage of the reaction. Metal dusting occurred only when graphite grew into the metal interior where the volume expansion is responsible for metal disintegration and dusting. It was also found that the metal dusting process could be significantly changed by alterations in alloy chemistry. Germanium was found to affect the iron dusting process by destabilising Fe3C but increasing the rate of carbon deposition and dusting, which questions the role of cementite in ferritic alloy dusting. Whilst adding copper to iron did not change the carburisation kinetics, cementite formation and coke morphology, copper alloying reduced nickel and nickel-base alloy dusting rates significantly. Application of these fundamental results to the dusting behaviour of engineering alloys is discussed.
关键词:
metal dusting
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